HAEMOPOIESIS (HAEMATOPOIESIS) Thank you ma'am for this excellent lesson delivery. I've discovered that HAEMOPOIESIS is the process by which blood cells are created. This process may alternatively be named HAEMATOPOIESIS. The produced constituents of blood include; 1. Red cells(erythrocytes) 2. White cells( leucocytes) 3. Platelets (thrombocytes). HAEMATOPOIESTIC SITES Adult's haematopoietic system begins in the embryonic yolk sac. Blood cells production move progressively in the liver, spleen and bone marrow as the embryo grows. Blood cell development before birth has many phases which include: 1. Mesoblastic stage- it takes place in the yolk sac and mesothelial layers of the placenta from zero to 2 months. 2. Hepatic stage- during this stage, blood cells are created in the liver and also the spleen and this might vary up to 7 months. 3. Myeloid stage- from the third month Upwards, the bone marrow increasingly becomes the major supplier of RBCs and other blood cells. Blood cells synthesis in the final month is entirely in the bone marrow. The bone marrow bis the single location of efficient haematopoiesis in mature human beings. In normal people, its daily output amounts to roughly 2.5 billion red cells and platelets with 1.0 billion granulocytes per kilogram of body weight. Haematopoietically active (red) marrow regresses after birth untill late adolescence at which time it is localized in the lower skull, vertebrae, shoulder and pelvic girdles, ribs and sternum. HAEMATOPOIETIC GROWTH FACTOR These are naturally occurring hormone-like glycoproteins (cytokines) necessary for the beginning and sustenance of appropriate proliferation And differentiation of haematopoietic progenitor cells and the function of adult blood cells. They act on stromal cells : IL-1, TNF. FUNCTIONS OF GROWTH FACTOR 1. Regulation of normal haematopoiesis in bone marrow 2. Induction of vell viability and cell proliferation. 3. Prevention of apoptosis of haematopoietic progenitor cells. 4. Stimulation of phagocytosis of bacteria 5. Enhancement of tumoridal activity of macrophages. The haematopoietic system is thus arranged in a system of hierarchy of cells in which multi potent haematopoietic stem cells will give birth to lineage committed progenitor cells which divide to form the maturing and mature blood cells. Morphologically, haematopoietic stem cells are undifferentiated and resemble tiny lymphocytes. CD34 is the best recognized marker of human stem and progenitor cells. Stem cells are capable of self renewal and differentiation. When they divide, they are responsible for creating all blood cells throughout life. While in steady state, stem cells divide only 50% of the daughter cells or average differentiate. The remaining 50% don't differentiate, but retain stem cell levels. CELLULAR RELEASE Cell migration from bone marrow to general circulation is entirely controlled by a complex interplay of signals from the bone marrow micro environment, circulating growth factors and cytokines and feedback mechanism that account for balanced generation of various blood cells. Cellular migration is under the control of a class of tiny cytokines called chemokines. To escape the bone marrow, the reticulocytes rely on a pressure gradient across the membrane to force it through the porosity. Blood cells travel from the bone marrow into the blood capillaries by these processes; HOMING and DIAPEDESIS. Homing is a process by which haemopoietic cells travel to certain tissues or organs in yhe body. Homing process contains a number of phases and they include; 1. Chemotaxis - cells follow gradients of signalling chemicals like chemokines. 2. Adhesion - capacity of cells to connect to endothelial cells that line the blood arteries 3. Extravasation - the capacity of cells to squeeze through the spaces between endothelial cells then move. CELL DEATH (APOPTOSIS) The ultimate step in the life of a blood cell is death and disposal via apoptosis. Apoptotic cell death is a process for disposing of undesirable or surplus cells. It occurs commonly in biological systems. It ensures the dispersion of cells without releasing any lysosomal or granule material that might provoke an inflammatory response. Apoptosis comprises a complicated set of processes that end in the activation of the caspase proteases, fragmentation of DNA and phagocytosis of apoptotic particles by macrophages. NOTE: 1. Stem cells are the most significant cells in haematopoietic cell creation. 2. They are ultimately responsible for rebuilding haemopoiesis after injury to the haematopoietic system by myelotoxic chemotherapy or after stem cell transplantations. This is performed via stem cell division, creating new stem cells to sustain the stem cell pool and developing cells that are the progenitor cells of each of the blood cells. 3. The final products of haematopoietic cell development are cells that are highly specialized for the varied tasks in the body.
Thank you Dr. for making this topic explanatory. Adult haemopoiec system originates from the embryonic yolk sac. -Blood cell before birth (Mesoblastic stage) -Hepatic stage (liver and spleen) -Myeloid(bone marrow becomes the site for blood cell production) The bone marrow is the sole site of effective haematopoesis in Adults. About 2.5 billion RBC, 2.5 billion platelets, and 1.0 billion granulocytes per body kilogram. Before age 5, all the bones in the body are involved in blood production. Summary of sites of haemopoiesis- For Fetus: 0-2 months, yolk sac) 2-7 (liver and spleen) 5-7 (Bone marrow) For Infants: Bone marrow (all the bones are involved) For adults: Sites like Vertebra, femur, allium,Sacrum, humerus, Skull. HGF- Haematopoetic growth factors Thank you Ma
Thank you so much Dr for this great lecture. I learnt that the function of the growth factor include the regulation of normal haematopoiesis in the bone marrow. Stimulation of phagocytosis of bacteria and induction of cell viability and cell multiplication. I also learned that the organisation of haem include Haematopoietic stem cells, pluripotent stem cells, myeloid and lymphoid progenitor cells. Thank you so much Ma
Thank you so much Dr, what a great lecture. HAEMOPOIESIS Is the process by which blood cells are formed from the haemopoietic system. STAGES OF BLOOD CELL FORMATION Mesoblastic stage: 0-2 months-yolk sac and mesothelial layers of the placenta Hepatic Stage: 2-7 months - liver and spleen Myeloid Stage: 5-9 months - bone marrow Bone marrow is the site of effective haemopoiesis in adults with daily production of : 2.5 billion RBCs, 2.5 billion platelets, & 1.0 billion granulocytes per kg of body weight. LIFESPAN OF BLOOD CELLS RBCs -120daya Platelets-7-10days HAEMOPOIETIC GROWTH FACTORS IL-1, TNF acts in stromal cells Stem cell factor, fit ligand: acts on pluripotential stem cells IL-3, GM-CSF, IL-6, G-CSF, thrombopoietin: acts on multipotential progenitor cells G-CSF, M-CSF, IL-5, Erythpoietin: acts on committee progenitor cells. FUNCTIONS OF THE GROWTH FACTORS Regulation of normal haemopoiesis in the bone marrow. Stimulation of phagocytosis of bacteria. Induction of cell viability and cell multiplication ORGANIZATION OF HAEM Haemapoietic stem cells Pluripotent stem cells Myeloid and lymphoid progenitor cells RBCs, Megakaryocytes, basophils CFU, Eosinophils CFU, Granulocytes and monocytes CFU, B-cells, T-cells, and NK cells Neutrophils, monocytes and dentritic cell APOPTOSIS: Is the final stage in the life of blood cells.
Thank you Ma’am for this wonderful lecture. HAEMOPOIESIS Is the process by which blood cells are formed from the haemopoietic system. STAGES OF BLOOD CELL FORMATION Mesoblastic stage: 0-2 months-yolk sac and mesothelial layers of the placenta Hepatic Stage: 2-7 months - liver and spleen Myeloid Stage: 5-9 months - bone marrow Bone marrow is the site of effective haemopoiesis in adults with daily production of : 2.5 billion RBCs, 2.5 billion platelets, & 1.0 billion granulocytes per kg of body weight. LIFESPAN OF BLOOD CELLS RBCs -120daya Platelets-7-10days HAEMOPOIETIC GROWTH FACTORS IL-1, TNF acts in stromal cells Stem cell factor, fit ligand: acts on pluripotential stem cells IL-3, GM-CSF, IL-6, G-CSF, thrombopoietin: acts on multipotential progenitor cells G-CSF, M-CSF, IL-5, Erythpoietin: acts on committee progenitor cells. FUNCTIONS OF THE GROWTH FACTORS Regulation of normal haemopoiesis in the bone marrow. Stimulation of phagocytosis of bacteria. Induction of cell viability and cell multiplication ORGANIZATION OF HAEM Haemapoietic stem cells Pluripotent stem cells Myeloid and lymphoid progenitor cells RBCs, Megakaryocytes, basophils CFU, Eosinophils CFU, Granulocytes and monocytes CFU, B-cells, T-cells, and NK cells Neutrophils, monocytes and dentritic cell APOPTOSIS: Is the final stage in the life of blood cells.
Thank you ma for this interesting lecture. Haemopoiesis is a process by which blood cells are formed. Adult haemopoietic system originates in the embryonic yolk sac. Blood cell production migrates sequential to the liver, spleen and bone marrow as the embryo develops. Blood cell formation has three stage: 1. Mesoblastic stage - occurs in the yolk sac and mesothelial Layers of the placenta. 2. Hepatic stage - occurs in the liver and spleen. 3. Myeloid stage - occurs in the bone marrow. Haemopoietic growth factor are naturally occurring like glycoproteins. They are required for initiation and sustainance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of mature blood cells. Functions of Growth factor includes: 1. Regulation of normal haemotopoiesis in the bone marrow. 2. Induction of cell viability and cell multiplication. 3.prevention of apoptosis of haemopoietic progenitor cells. 4. Stimulation of phagocytosis of bacteria. 5. Enhancement of fumoridal activity of macrophages.
Thank you for this enlightening lecture on Haemopoiesis Here's my summary; Haemopoiesis Also known as haematopoiesis is the process by which blood cells are formed. The formed blood cells are Red Blood cells (Erythrocytes) White blood cells( leukocytes) PlateletsThrombocytes) Sites of Haemopoiesis Fetus: 0-2 months_Yolk sac 2-7 months _Liver, spleen 5-9 months _ Bome marrow Infants Bone marrow Adults Vertebrae, ribs, skull, sacrum, pelvis, proximal ends of femur and humeri,sternum and ileum. Haemopoetic Growth Factors These are naturally occurring hormone-like glycoproteins (cytokines) that are required for the initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells and the formation of mature blood cells. Examples of such factors are as follows: interleukin-1, Tumor Necrosis Factor, interleukin-3, GM-CSF, interleukin-6, interleukin-5 etc Functions of the Growth factors Formation of normal Haemopoiesis in the bone marrow Induction of cell viability and cell multiplication Prevention of apoptosis of haemopoietic progenitor stem cells Enhancement of tumoridal activity of macrophages Organisation of haemopoietic system The haemopoietic system is a hierarchy of cells in which multipotent haemopoietic stem cells gives rise to lineage-committed progenitor cells, which divides to generate the maturing and the matured blood cells. Morphological, Haemopoietic stem cells are undifferentiated and resembles Small lymphocytes. CD34 is the best known marker of human stem and progenitor cells. Haemopoietic Ontogeny Through division and differentiation, the pluripotent cells mature to multipotent mixed myeloid and lymphoid progenitor cells. Further division and maturation gives rise to committed cells The uncommitted lymphoid stem cells differentiate to B lymphocytes, T lymphocytes and Natural Killer cells Cellular Release Cell migration from bone marrow to the general circulation is tightly regulated by a complex interplay of signals from the bone marrow micro environment, circulatory growth factors and cytokines and feedbacks mechanisms that accounts for balanced production of different blood cells To leave the marrow, the reticulocyte depends on a pressure gradient across the membrane to drive it through the pore The processes involved includes; Honing and diapedesis
Thank you, Ma, for this important lecture. In summary, i learnt that HAEMOPOIESIS is the process by which blood cells are formed from the haemopoietic system. STAGES OF BLOOD CELL FORMATION Mesoblastic stage: 0-2 months-yolk sac and mesothelial layers of the placenta Hepatic Stage: 2-7 months - liver and spleen Myeloid Stage: 5-9 months - bone marrow Bone marrow is the site of effective haemopoiesis in adults with daily production of : 2.5 billion RBCs, 2.5 billion platelets, & 1.0 billion granulocytes per kg of body weight. LIFESPAN OF BLOOD CELLS RBCs -120days Platelets-7-10days HAEMOPOIETIC GROWTH FACTORS IL-1, TNF acts in stromal cells Stem cell factor, fit ligand: acts on pluripotential stem cells IL-3, GM-CSF, IL-6, G-CSF, thrombopoietin: acts on multipotential progenitor cells G-CSF, M-CSF, IL-5, Erythpoietin: acts on committee progenitor cells. FUNCTIONS OF THE GROWTH FACTORS Regulation of normal haemopoiesis in the bone marrow. Stimulation of phagocytosis of bacteria. Induction of cell viability and cell multiplication. ORGANIZATION OF HAEM Haemapoietic stem cells Pluripotent stem cells Myeloid and lymphoid progenitor cells RBCs, Megakaryocytes, basophils CFU, Eosinophils CFU, Granulocytes and monocytes CFU, B-cells, T-cells, and NK cells Neutrophils, monocytes, and dentritic cell APOPTOSIS is the final stage in the life of blood cells.
Thank you Dr, for this informative lecture I learnt that Haemopoiesis is the process by which blood cells are formed. And they are different site of Haemopoiesis which are FETUS: 0-2months (Yolk sac) 2-7months (Liver, Spleen) 5-9months (Bone marrow) INFANTS: Bone marrow (All bones) ADULTS: Vertebrae, Ribs, Skull, Sacrum I also learnt about the haemopioetic sites and haemopioetic growth factors The functions of the growth factors include: A)Bacterial phagocytosis B)Prevention of apoptosis in heamopoietic stem cells C)Enhancement of tumoreghal activities of macrophages D)Induction of cell viability and multiplication And lastly,I learnt the stages of hemopioetic cell development which starts with the Haemapoietic stem cells, Stem cell are capable of self renewal, they give rise to lineage selection, differentiated into myeloid and lymphoid lineage which are involved in T and B lymphocyte, and Natural killer cells goes to maturation and carry out their functions and undergo apoptosis.
Thank you Dr. For this interesting lecture. I learnt that, Haemopoiesis is the process of blood cell formation, occurring primarily in the bone marrow, liver, spleen, and embryonic sac during development. It proceeds through stages from pluripotent stem cells to committed progenitor cells, leading to the production of mature blood cells. Hormone-like growth factors regulate haemopoiesis, acting on stromal cells, pluripotent stem cells, and committed progenitor cells to ensure normal proliferation and differentiation.
Thank you ma for this lecture. I learnt that Haemopoiesis is the process by which blood cells are formed and it's also called Haematopoiesis. Formed elements of the blood include; • RBCs - Erythrocytes • WBCs - Leukocytes • Platelets - Thrombocytes Haemopoietic sites include the adult haemopoietic system originates in the embryonic yolk sac and Blood cell production migrates sequentially to the liver,spleen & bone marrow as the embryo develops. Summary of this sites are; ● Foetus- 0 to 2months(yolk sac) - 2 to 7months(Liver,spleen) - 5 to 9months(Bone marrow) ● Infants - Bone morrow(all bones) ● Adults - Vertebrae, ribs,skull,sacrum & pelvis,proximal ends of femur & humerus, sternum and ileum. Haemopoietic growth factors are naturally occurring hormone like glycoproteins(cytokines) and blood HGF levels rise during infection or following chemotherapy / irradiation. Functions of Growth factor are regulation of normal haematopoiesis in the bone marrow,stimulation of phagocytosis of bacteria, induction of all viability & cell multiplication,etc. Stages in haemopoietic cell development is Stem cell - Pluripotent stem cells - Divides to either myeloid progenitor or lymphoid progenitor. Human stem cells and most haemopoietic rogenitor cells are CD34 positive & CD38 negative. Haemopoietic stem cells are multipotent and can differentiate to all types of stem cell. Cell migration from bone marrow to the general circulation is tightly by a complex interplay of signals from the bone marrow micro environment, circulating growth factors and cytokines and feedback mechanisms that accounts for balance production of different blood cells. Blood cells pass from the bone marrow into the blood capillaries through the processes of Homing & Diapedesis. Homing is a process by which haemopoietic cells move to specific tissues and organs in the body. Diapedisis is the ability of cells squeezing through the poles of the capillary membrane.
Thank you very much for the lecture Dr. Ify.. I learnt that hemopoiesis is simply the process by which blood cells are formed. Hemopoietic sure includes; 1. Embryonic yolk sac 2. Liver 3. Spleen 4. Bone marrow Also blood cell formation before birth includes; 1. Mesoblastic stage: This occurs in the yolk sac and mesothelial layer of the placenta. This takes place from 0-2 months. 2. Hepatic stage: In this stage, the liver and the spleen is the site of blood production. This occurs from 2-7 months 3. Myeloid stage: The main source of production is the bone marrow. It is from 5th- 9th month. The function of growth factors includes: 1. Regulation of normal hemopoiesis to bone marrow. 2. Prevention of apoptosis of haemopoietic progenitor cells 3. Induction of cell viability and cel multiplication.. Thanks you ma for a wonderful lecture..
Thanks Dr, for this eye opening teaching, indeed it’s worth recommending. I understood that Hemopoiesis is the process by which blood cells are formed (formation of blood) and can be called haematopoiesis. This further goes down to elements of blood which are 1. Red cells (Erythroblasts) 2. White cells (Leukocytes) 3. Platelets (thrombocytes) The process by which the above blood cells are formed is called Hematopoiesis HEMATOPOIETIC SITES (A) Megaloblastic stage: blood cell formation occurs in the yolk sac and mesothelial layers of the placenta, this occurred for about two months of gestation (B) Hepatic stage: blood cell formation occurs in the liver and the spleen (C) Myeloid stage: This is simply the stage where the bone marrow is involved in the blood cell formation and production ( from third months up, the bone marrow becomes the principal site of RBCs and other cells N/B: > The bone marrow is the sole site of effective hematopoiesis in adult >when a child is below 5years, all the sites and bone in the system are involved in the blood cell production >By 18years, hematopoietic marrow is only found in vertebrae, ribs, skull, pelvis, and proximal epiphyses of the femora and humeri HEMOPOIETIC GROWTH HORMONES (HGF): are naturally occurring hormones, they are required for initiation and sustainance of normal proliferation and differentiation of haemopoietic progenitor cells and formation of mature blood cells Functions of the growth hormone 1. Regulation of normal haematopoiesis in the bone marrow 2. induction of cell viability and cell multiplication 3. prevention of apoptosis of haematopoietic progenitor cells 4. stimulation of phagocytosis of bacteria 5. enhancement of tumoridal activity of the macrophages I really enjoyed this lecture Dr
Thank you for the lecture Ma. I learnt that Haemopoiesis, the process of blood cell formation, occurs in several sites throughout development. Initially, in the mesoblastic stage, it takes place in the yolk sac and placenta's mesothelial layers. This is followed by the hepatic stage, where the liver and spleen become involved in blood cell production. Ultimately, from the myeloid stage onwards, the bone marrow becomes the primary source of red blood cells (RBCs) and other blood cells. At birth, the bone marrow becomes the exclusive site for hematopoiesis in adults. Haemopoietic growth factors (HGFs) are natural glycoprotein hormones that regulate normal haemopoiesis, promote cell viability and multiplication, prevent apoptosis of haemopoietic progenitor cells, stimulate phagocytosis of bacteria, and enhance macrophage tumoridal activities. Haemopoietic cell development involves various stages, starting from stem cells giving rise to lineage-committed cells, including myeloid and lymphoid lineages. The myeloid lineage produces RBCs, platelets, and various types of white blood cells, while the lymphoid lineage generates B-lymphocytes, T-lymphocytes, and NK cells, which undergo maturation before exhibiting their functions and undergoing apoptosis. Blood cells move from the bone marrow into the bloodstream through the processes of homing and diapedesis. Homing involves chemotaxis, adhesion, extravasation, and migration of haemopoietic cells to specific tissues or organs. Diapedesis refers to the ability of cells to squeeze through capillary membrane pores.
Thanks ma’am, this is an interesting lecture. I learnt the following lessons; Haemopoiesis, also known as hematopoiesis, is the process by which the body produces new blood cells. It occurs primarily in the bone marrow, where stem cells differentiate into various types of blood cells, including red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). This process is crucial for maintaining the body's blood cell levels and overall health. HAEMOPOIETIC GROWTH FACTORS IL-1, TNF acts in stromal cells Stem cell factor, fit ligand: acts on pluripotential stem cells IL-3, GM-CSF, IL-6, G-CSF, thrombopoietin: acts on multipotential progenitor cells G-CSF, M-CSF, IL-5, Erythpoietin: acts on committee progenitor cells. FUNCTIONS OF THE GROWTH FACTORS Regulation of normal haemopoiesis in the bone marrow. Stimulation of phagocytosis of bacteria. Induction of cell viability and cell multiplication ORGANIZATION OF HAEM Haemapoietic stem cells Pluripotent stem cells Myeloid and lymphoid progenitor cells RBCs, Megakaryocytes, basophils CFU, Eosinophils CFU, Granulocytes and monocytes CFU, B-cells, T-cells, and NK cells Neutrophils, monocytes and dentritic cell
Thankyou for the lecture. Here is the summary of my haematopoiesis: Hematopoiesis in infants primarily occurs in the liver and spleen, while in adults, it mainly takes place in the bone marrow of the long bones such as the femur and pelvis. Blood formation starts during fetal development and shifts to different locations as the body matures. The liver is involved in blood formation during early development, but the bone marrow becomes the primary site for adult blood cell production.
Thank you Ma for this insightful lecture. From the video I understood that haemopoiesis is the process by which blood cells are formed. At embryonic stage, the process is done on the yolk sac which the origin of adult blood system. Subsequently it migrates to the liver then the spleen and finally the bone marrow. Generally blood cells uncommitted progenitors are pluripotent stems cell. Haemopoiesis has 1. Mesoblastic Stage - up 2 months 2. Myeloid stage -:From the 3 month onwards when the bone becmes chiefly involved 3. Hepatic stage - up 7 months where the liver and spleen are involved Haemopoiesis growth factors are naturally occurring proteins like cytokines which are required for proper dissociation and maturity of progenitor, proliferation, maturity and normal functions blood cells. Some of their functions include; 1. Regulate normal haemopoiesis in bone marrow 2. Prevent apoptosis of progenitor call 3. Responsible for blood cells viability Stem cells are capable of self renewal and pluripotent in nature, can differentiate to Lineage selection and can undergo programmed cell death
Thank you ma, in summary, haemopoiesis also known as haematopoiesis is defined as the process by which blood cell are formed. The formed cells are: leukocytes, erythrocytes, thrombocytes. Adult haemopoietic system originates in embryonic yolk sac, blood cell production migrates sequentially to the liver, spleen and bone marrow as the embryo grows. Blood cell formation before birth and after birth was taught, summary of sites of haematopoiesis, haematopoietic growth factors, organization of haematopoietic system, haematopoietic ontogeny, cellular releaseans cellular migrations such as homi ng, adhesion, extravasation, diapedesis. The final stage in the life of a blood cell is death and disposal by apoptosis(programmed cell death). The end products of haemopoietic cell development are cells that are highly specialized for their different functions in the body. RBCs for oxygen transport, WBCs for defence, platelets for blood coagulation.
Wow🤩 what a great lecture on Haemopoiesis. In summary, I learnt that Haemopoiesis or Haematopoiesis is simply the process by which blood cells (Erythrocytes, leucocytes and thrombocytes) are formed. Haemopoietic sites where this happens are: 1. Embryonic yolk sac 2. Liver 3. Spleen 4. Bone marrow. Blood cell formation before birth: Mesoblastic stage- 2 months of gestation Hepatic stage- 7 months of gestation Myeloid stage- 3 months above. Haemapoietic growth factors are naturally-occuring hormone-like glycoproteins (cytokines), required for initiation and sustenance of normal proliferation and differentiation haemopoietic progenitor cells and the function of mature blood cells. Thank you ma'am😊
I learnt that haemopoiesis is the process by which blood cells are formed, this blood cells include erythrocytes, leucocytes and platelets, i also learnt about the stages of hemopoiesis including mesoblastic stage, hepatic stage and myeloid stage, i also learnt about the hemopoietic sites of blood production, the hematopoietic growth factors, the functions of growth factors, the stages of hematopoietic cell development, how cell are released and finally apoptosis which is programmed cell death. I also learnt that stem cells are capable of self renewal and differentiation when they divide and are responsible for producing all blood cells throughout life. Thank you ma
Thank you Ma'am for this lecture. I learnt that Haemopoisesis is the process by which blood cells are created. I also learnt about the different sites of Haemopoises whiche are... 1) Festus : 0-2 months (Yolk Sac) 2) 2-7 months (Liver, Spleen) 3) 5-9 months (Bone marrow) 4) Infants : Bone marrow (All bones) 5) Adults: Vetebrae, ribs, skull, sacrum, pelvis, proximal ends if femur and humeri, sternum Haemopoietic growth factors (HGF) are naturally occuring hormone like glycoprotein. Some of the function of Haemopoietic growth factors includes i) Regulation of normal lHaemopoietic in the bone marrow. ii) induction of cell viability and cell multiplicatiomultiplication iii) prevention of apoptosis of haemopoietic progenitor cells iv) Stimulation of phagocytosis of bacteria v) Enhancement of tumoridial activities of macrophages. In the Organization of haemopoietic system, the haematopoietic system is an hierarchy of cells in which multipotent haemopoietic stem cells give rise to lineage projenitor cells divides into maturing and mature blood cells. I understood that Homing is a process by which haemopoeitic cells move to specific tissues or organs in the body while Diapedesis (ability of cells squeezing through the pores of the capillary membrane. This involves a series of steps, namely. •Chemotaxis •Adhesion •Extravasation •Migration
Thank you ma for the lecture. From the lecture I learnt that Hemopoiesis is the formation of blood cells(Erythrocytes, Leucocytes and thrombocytes). The sites hematopoiesis in different stages of development: In embryonic stage that is before birth,it is the yolk sac and placenta called mesoblastic stage. Hepatic stage occurs at 2 to 7 months at the liver and spleen. Myeloid stage is where the bone marrow takes over hemopoiesis. At birth, all the bones are involved in cell production Upto 5 years. In adolescents and adults, the vertebrae,ribs skull and other sites takes over. Hemopoietic growth factors are cytokines needed for regulation of haemopoiesis in bone marrow,sustaining the proliferation and differentiation of progenitor cells or stem cells into mature blood cells,stimulating bacteria phagocytosis,prevents destruction of hemopoietic progenitor cells. Haemopoietic system is a hierarchy of cells where multipotent haemopoietic stem cells produces committed progenitor cells which divide to generate mature blood cells. CD34 is the best marker of human stem and progenitor cells. Only 50% of the HSC differentiate into committed cells, the other 50% maintain HSC numbers. HSC differentiate into committed cells, these cells mature and enter the system(blood) and die after it has finished it's work. At each stage of blood cell production,there are different haemopoietic growth factors acting on it: IL-1 and tumor necrosis factor(TNF) acts on stromal cells. Stem cell factor and fit ligands acts on pluripotent stem cells. GM-CSF,IL-6,IL-3,G-CSF and thrombopoietin acts on multipotent progenitor cells. IL-3 acts on committed progenitor cells. When cells are matured in bone, they migrate from bones to blood, this process is regulated by releasing factors. Blood cells pass from boner marrow to blood capillaries through processes like Homing and Diapedesis.
Thank you ma for this educative lecture In summary I learnt that haemopoiesis is the process by which blood cells are formed. The stem cells are the most important cells in haemopoietic cell production, they are ultimately responsible for regenerating haemopoiesis following damage to the haemopoietic system by myelotoxic chemotherapy or after stem cell transplantation. The end products of haemopoietic cell development are cells that are highly specialized for their different functions in the body ... I also learnt that haemopoietic growth factor are naturally occurring hormone like glycoproteins i.e cytokines that are required for initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells and the functions of nature blood cells.. Its functions are . Prevention of apoptosis of haemopoietic progenitor cells. . Helps in stimulation of phagocytosis of bacteria. . Enhancement of tutorial activity of macrophages. . Also for regulation of normal haemopoiesis in the bone marrow.
Thank you Ma for the teaching. I learnt that Haematopoiesis or haemapoiesis is the process by which blood cells are formed. The site for adult haemopoietic system is the embryonic yolk sac. As the adult grows, there is migration from the yolk sac to the spleen, liver and bone marrow. I also learnt the stages in haemopoietic cell development . The teachings were understood. Thank you very much Ma 🙏
Thanks Doc. for the lecture. I learnt that stem cells are capable of self renewal and differentiation when they divide and are responsible for producing all blood cells throughout life.
This session is thrilling, all thanks to you ma. I learnt about Haematopoesis as a process by which blood cells are formed. Went further to explain elements of blood formed as: -Red blood cells -White blood cells -Plateletes Haematopoietic sites min adult system originates in the embryonic yolk sac. I also learnt haematopoietic sites includes; -Embryonic yolk sac -Spleen -Liver -Bone marrow I learnt that before birth blood is formed in stages and these stages includes; 1. Mesoblastic stage from yolk sac and mesothelial layers of the placenta. it occurs up to 2 months of gestation. 2. Hepatic stage from Liver and sometimes spleen. (Up to 7 months). 3. Myeloid stage from the third month onwards, the bone marrow gradually becomes the principal source of RBCs and other blood cells. In normal adult, production bof blood cells daily is; -2.5 billion red cells -2.5 billion platelets -1.0 billion granulocytes per weight of the body. After birth and adolescence, active red marrow regresses and focuses on the liver, spleen, vertebrae, shoulder, ribs etc. Below 5 years, all bones are involved in haematopoesis. We went further to look at Haematopoietic Growth Factor as naturally occurring hormone like glycoproteins(Cytokines). we saw it functions as; 1. Regulation of normal Haematopoesis in bone marrow. 2. Induction big cell availability and cell multiplication. 3. prevention big Apoptosis of haematopoietic progenitor cells. 4. stimulation of phagocytosis not bacteria. 5. Enhancement of fumoridal activity of macrophages. We saw the organization of the haematopoietic system and we saw that it is a hierarchy of cells in which haematopoietic stem cells give rise to lineage committed progenitor cells which later divides to generate the matured red blood cells. Human stem cells is regulated by a series of molecules known as Cytokines which includes; -Interleukins -Stimulating factors. I learnt about Homing and Diapedesis. I saw Homing as a process by which haematopoietic cells move to specific tissues and organs. Diapedesis is the ability of cells to squeeze through the gaps between the poles of the capillary membrane. Lastly, I saw that stem cells are the most important cells in haematopoietic cell production.
Thank you ma for this wonderful lecture. I got to understand that Haemopoiesis is a process by which blood cells are formed. Adult haemopoietic system originates in embryonic yolk sac. Blood cell Formation occurs in three stages before birth; -Megaloblastic stage -Hepatic stage - Myeloid stage. I also learnt about the Haemopoietic Growth Factors. The HGFs are naturally occurring hormone-like glycoproteins required for the initiation and sustenance of normal proliferation of Haemopoietic progenitor cells. Functions of the growth factors includes; -Regulation of normal hematopoiesis in the bone marrow. -Induction of cell variability and cell multiplication. -Prevention of apoptosis of Haemopoietic progenitor cells. Lastly, i learnt about the sites of Haemopoiesis. In fetus, at 0-2months is found in yolk sac, at 2-7 months it's being found in the liver& spleen and at 5-9 months it is being found in the bone marrow. In infants, it is being found in the bone marrow while in Adults it is found in vetebrae,ribs,skull,sacrum&pelvis.
Thank you ma for the lecture. I learnt that hematopoiesis is the process by which the body produces blood cells. This process begins in the bone marrow, where stem cells give rise to red blood cells, white blood cells, and platelets. First, the stem cells differentiate into different types of progenitor cells, such as red blood cell precursors and white blood cell precursors. Next, the progenitor cells mature into fully functioning blood cells, which are then released into the bloodstream to carry out their various functions. The entire process of hematopoiesis is regulated by various factors, including hormones, enzymes.
Thank you ma for this lecture. In summary, hematopoiesis is the formation of blood cells. Adult haemopietic system originates in the embryonic yolk sac. Blood cell formation before birth includes mesoblatic stage , hepatic stage, myeloid stage . The marrow is the sole site of effective haemopoiesis in adult. Haemopietic growth factor are naturally occuring hormone like glycoproteins required for initiation and sustenance for normal proliferation and differentiation of haemopietic progenitor cell and the function of mature blood cells. Haemopietic system is a hierarchy of cells in which multipotent haemopietic stem cells give rise to lineage committed progenitor cell which divide to generate the maturing and mature blood cells. Stem cells are capable of cell renewal and differentiation when they divide are responsible for providing blood cells throughout life. Hematopoietic stem cells are multipotent and differentiate to all type of stem cells. Cytokines controls the proliferation, differentiation of different blood cells. In cellular release, blood cells pass from the bone marrow into the blood capillaries through the process of homing and diapedesis.
Thank you so much Dr. I learnt alot from this class. In summary, I learnt that haemopoiesis is the process by which Blood cells are formed. This is basically the formation of blood cells. The formed element of blood cells ; Red cells, white cells and platelets. The site of haemopoietic are: 1. Mesoblastic stage: This occurs in the yolk sac and mesothelial layer of the placenta. This takes places from zero to 2 months. 2. Hepatic stage: here, the liver and spleen is the site of blood production. This takes place from 2-7months. 3. Myeloid stage: in this stage, the bone marrow is the main source of production. This from 5-9month. I learnt that the lifespan of blood cells for RBC is 120days, and that of platelets is 7-10days. I also got to learn about the function of the growth factors. 1. Regulation of nomal haemotoposis to bone marrow. 2. Induction of cell viability and cell multiplication. 3. Prevention of apoptosis of haemopoietic progenitor cells. Thank you so much, Dr. This is indeed insightful.
Thanks ma for this video on HAEMOPOIESIS. I understood that haemopoiesis is the process by which blood cells are formed and RBC , WBC and platelets are formed elements of blood. I also understood that adult haemopoietic system originates in the embryonic yolk sac. Blood cell formation before birth , we have the 1.Mesoblastic stage 2.Hepatic stage 3.Myeloid stage.The bone marrow is the sole site of effective haematopoiesis in adult human beings. By the age of 18 years haematopoietic marrow is found only in the vertebrae, ribs , skull , pelvis and proximal epiphyses of the femora and humeri. I understood that haemopoietic growth factors are naturally occurring hormone like glycoproteins required for initiation and substance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of mature blood cells. One of the functions of the growth factors includes regulation of hormonal haematopoiesis in the bone marrow. I understood Homing is a process by which haemopoietic cells move to specific tissues or organs in the body while Diapedesis (ability of cells squeezing through the pores of the capillary membrane).
Thank you ma for this educative lecture. At the end of this lecture, I gained an understanding that Haemopoiesis encompasses the formation of blood cells, occurring across various sites within the body. Before birth, this process unfolds through three distinct stages: Mesoblastic stage: transpiring within the yolk sac and mesothelial layers of the placenta during the initial 0-2 months of gestation. Hepatic stage: transitioning to the liver and spleen from 2-7 months of gestation. Myeloid stage: commencing from 5-8 months onwards, where the bone marrow gradually emerges as the primary source for red blood cells (RBCs) and other blood cell types. Furthermore, I learnt that at birth, the bone marrow assumes the role of exclusive production site, serving as the sole location for effective hematopoiesis in adults. Next, I learnt on Haemopoietic Growth Factors (HGF), acting as naturally occurring hormone-like glycoproteins. These factors play pivotal roles, including regulation of normal haemopoiesis in the bone marrow, induction of cell viability and multiplication, prevention of apoptosis in haemopoietic progenitor cells, stimulation of bacterial phagocytosis, and enhancement of macrophage tumoridal activities. Additionally, the lecture delved into the multifaceted stages of haemopoietic cell development, beginning from the stem pool, where cells renew and differentiate into lineage-committed cells-myeloid and lymphoid lineages. The myeloid lineage yields various blood cell types such as red cells, platelets, eosinophils, neutrophils, and basophils, while the lymphoid lineage gives rise to B-lymphocytes, T-lymphocytes, and NK-cells. These cells progress through maturation stages, fulfilling their diverse functions before ultimately undergoing apoptosis. Thank you
Thank you ma for the lecture, hematopoiesis is the process by which the body produces blood cells. This process begins in the bone marrow, where stem cells give rise to red blood cells, white blood cells, and platelets. First, the stem cells differentiate into different types of progenitor cells, such as red blood cell precursors and white blood cell precursors. Next, the progenitor cells mature into fully functioning blood cells, which are then released into the bloodstream to carry out their various functions. The entire process of hematopoiesis is regulated by various factors, including hormones, enzymes.
Thank you ma'am for this interesting lecture. I've learned that: HAEMOPOIESIS is the process by which blood cells are formed. This process can also be called HAEMATOPOIESIS. The formed elements of blood include; 1. Red cells(erythrocytes) 2. White cells( leucocytes) 3. Platelets (thrombocytes). HAEMATOPOIESTIC SITES Adult's haematopoietic system originates in the embryonic yolk sac. Blood cells production migrate sequentially at the liver, spleen and bone marrow as the embryo develops. Blood cell formation before birth has various stages which include 1. Mesoblastic stage- it takes place at the yolk sac and mesothelial layers of the placenta from zero to 2 months. 2. Hepatic stage- at this stage, blood cells are formed in the liver and also the spleen and this could range up to 7 months. 3. Myeloid stage- from the third month Upwards, the bone marrow gradually becomes the principal source of RBCs and other blood cells. Blood cells production in the last month is exclusively in the bone marrow. The bone marrow bis the sole site of effective haematopoiesis in adult human beings. In normal adults, its daily production amounts to about 2.5 billion red cells and platelets with 1.0 billion granulocytes per kilogram of body weight. Haematopoietically active (red) marrow regresses after birth untill late adolescence after which time it is focused in the lower skull, vertebrae, shoulder and pelvic girdles, ribs and sternum. HAEMATOPOIESTIC GROWTH FACTOR These are naturally occurring hormone-like glycoproteins (cytokines) required for the initiation and sustenance of normal proliferation And differentiation of haematopoietic progenitor cells and the function of mature blood cells. They act on stromal cells : IL-1, TNF. FUNCTIONS OF GROWTH FACTOR 1. Regulation of normal haematopoiesis in bone marrow 2. Induction of vell viability and cell multiplication. 3. Prevention of apoptosis of haematopoietic progenitor cells. 4. Stimulation of phagocytosis of bacteria 5. Enhancement of tumoridal activity of macrophages. The haematopoietic system is so organized in a system of hierarchy of cells in which multi potent haematopoietic stem cells will give rise to lineage committed progenitor cells which divide to generate the maturing and mature blood cells. Morphologically, haematopoietic stem cells are undifferentiated and resemble small lymphocytes. CD34 is the best known marker of human stem and progenitor cells. Stem cells are capable of self renewal and differentiation. When they divide, they are responsible for producing all blood cells throughout life. While in steady state, stem cells divide only 50% of the daughter cells or average differentiate. The remaining 50% don't differentiate but maintain stem cell numbers. CELLULAR RELEASE Cell migration from bone marrow to general circulation is totally regulated by a complex interplay of signals from the bone marrow micro environment, circulating growth factors and cytokines and feedback mechanism that account for balanced production of different blood cells. Cellular migration is under the control of a family of small cytokines termed chemokines. To leave the bone marrow, the reticulocytes depend on a pressure gradient across the membrane to drive it through the pore Blood cells pass from the bone marrow into the blood capillaries through these processes; HOMING and DIAPEDESIS. Homing is a process by which haemopoietic cells move to specific tissues or organs in yhe body. Homing process involves a series of steps and they include; 1. Chemotaxis - cells follow gradients of signalling molecules like chemokines. 2. Adhesion - ability of cells to attach to endothelial cells that line the blood vessels 3. Extravasation - the ability of cells to squeeze through the gaps between endothelial cells then migrate. CELL DEATH(APOPTOSIS) The final stage in the life of a blood cell is death and disposal by apoptosis. Apoptotic cell death is a mechanism for disposing of unwanted or excess cells. It occurs widely in biological systems. It ensures the distribution of cells without releasing any lysosomal or granule content that would cause an inflammatory reaction. Apoptosis involves a complex series of events that culminate in the activation of the caspase proteases, fragmentation of DNA and phagocytosis of apoptotic bodies by macrophages. NOTE: 1. Stem cells are the most important cells in haematopoietic cell production 2. They are ultimately responsible for regenerating haemopoiesis following damage to the haematopoietic system by myelotoxic chemotherapy or after stem cell transplantations. This is accomplished by stem cell division, producing new stem cells to maintain the stem cell pool and differentiating cells that are the progenitor cells of each of the blood cells. 3. The end products of haematopoietic cell development are cells that are highly specialized for the different functions in the body.😮
Thank you very much ma. I learnt that hematopoiesis is simply the process of which blood cells are form . It begins right from embryonic life in the yolk sac till adult Life when it is fully the responsibility of membranous bone marrow. It follows; 0-2 month - yolk sac 2-7 month - fetal liver and sleen 5 month- adolescence - all bone marrow Adult - membranous bones. On daily basis hematopoiesis is going on ,with the daily production of blood cells per kg of body weight; 2.5 billion of RBC 2.5 billion of platelets 1 billion of granulocytes. It is important to note that the activeness of the red bone marrow depletes as one grows until late adolescence when it is fully focused on membranous bones eg. Skull, ribs, vertebrae , sternum, femoral. This is because the red bone marrow is replaced with yellow bone marrow which doesn't take part in blood cells production. This process is influenced by several growth factor/ hormones acting on the various stages of the process. They regulate hemopoietic process, prevent abnormal apoptosis of progenitor cels and induce viability of cells for hemopoiesis; some act on stroma cell ( IL-1, TNF) , some on multipotent progenitor cell( IL-3,:GM- CSF, G-CSF,IL-6) some on the committed progenitor cell (G-CSF,M-CSF, Erythropoietin, thrombopoietin etc) Stages of hemopoiesis: It begins with the undifferentiated stem cells which give rise to the pluripotent stem cells which then give rise to the myleloid and lymphoid progenitors which proliferate into the blood forming cells and lymphoid forming cells respectively. The blood forming cells give rise to blood cells; RBC, WBCs while the lymphoid forming cells give rise to the T and B lymphocytes and natural killer cells. These cells produced in the bone marrow now Carry out homing and diapedesis in order to reach the circulation and various points to location and function.
Thank very much for the lecture. I learnt what Hemopoiesis is all about. Which by definition is the process by which blood cells are formed. The sites at which this blood cells are formed are: Mesoblastic stage, It takes place in the yolk sac , from 2months birth before birth. Hepatic stage, which takes place in the liver,spleen. From 7 months. And Myeloid stage, at this stage the bone marrow is gradually becomes the principle source of the RBCs and other blood cells. Then at the last month, bone marrow exclusively. Hemopoietic growth factors are naturally occurring hormone like glycoproteins(cytokines). One of the function is It regulate the normal haematopoiesis in the bone marrow . The stages in haemopoietc cell development are : From the stem cell pool , to the Renewal which can reverse back the stem cell, gets to differentiation were it migrate to the lineage selection and gets to mature and start functioning , until cell death (apoptosis). Thank you ma
thank you ma for this amazing lecture in summary,Hemopoiesis is defined as the process where red blood cells are formed . the formed blood cells are -Leukocytes -Erythrocytes -Thrombocytes blood cell production in infant 0-2months=Yolk sac 2-7months=Liver ,Spleen 5-9months =Bone marrow in infant =bone marrow in adult=vertebrae ,ribs ,skull,Femur cell migration from the bone marrow to the general circulation is tightly by a complex interplay of signals from the bone marrow environment,circulating growth factor and cytokines are feedback mechanism that account for balance productivity of different blood cells . Haemopoetic growth factors are naturally occurring hormones like glycoproteins.blood HGF level rise during infection. Functions of growth factor are -regulation of normal haemopoesis in the bone made -it is involved in the apoptosis of haemapoetic proginator cells - Stimulatin of phagocytosis of bacteria .
Thank you, Dr. I learnt that , haemopoiesis is the process by which blood are formed. And they are different site of haemopoiesis which are; Festus:0-2 months ( yolk sac) 2-7 months(liver and spleen) 5-9 month (bone marrow) Infants :bone marrow (all bones) Adults:vertebrae,ribs,skull,serum and pelvis . The haemopoiesis follows a hierarchical organization, starting with multipluripotent haemopoiesis stem cells that give rise to committed progenitor cells. Haemopoiesis stem cell is also on as HAEMOCYTOPLAST CYTOKINES.
Thank you so much Dr. Moral lessons: Haematopoiesis (Haemopoiesis): is the process by which blood cells are formed. Forms of element: The Red cell--- Erythrocytes White cells ----- Glucocyte Platelets ---- thrombocyte Blood cell formation before Birth: 1. Mesoblastic stage -- 0 to 2 months of Gestation 2. Hepatic stage --- the liver and the spleen forms the blood cells and take charge of blood production for upto 7 months. 3. Myeloid stage: from the third month onwards the bone marrow gradually becomes the principal source of the red blood cells and other blood vessels. HAEMOPOIETIC GROWTH FACTORS: These are naturally occurring hormone-like glycoproteins(cytokines) -- required for initiation and sustenance of normal proliferation and differentiation of HAEMOPOIETIC progenitor cell's and the formation of mature blood cells. Thank you Ma🙏 3
Thank you Doctor for this lecture. It was an amazing insight coming from you ma This lecture has given me a clear understanding of Haemopoeisis which is the process by which blood cells are formed and it's site of which it originates in the embryonic yolk sac and also learnt about the stages involved in the formation of blood cells. God bless you ma'am
Thank you so much for this wonderful lecture. I was able to understand that haemopoiesis is the process of blood cells formation. I was also able to understand the different haemopoietic sites which are; - Originally the embryonic yolk sac - liver - spleen - bone marrow I was able to understand the various stages of haemopoiesis before birth which are; - Mesoblastic stage which occurs at about two months of gestation in the yolk sac and mesothelial layers of the placenta. - Hepatic stage which occurs from the second to the seventh month where the liver and the spleen begin to produce blood cells taking over from the yolk sac. - Myeloid stage where from the third month onwards, the bone marrow begins to produce blood cells with the liver and spleen slowly relinquishing this responsibility to the bone marrow. Thank you ma
Thank so much Dr. In summary, I have learned that Hematopoiesis denotes the process of blood cell formation, encompassing the production of red blood cells, white blood cells, and platelets. It occurs at various hematopoietic sites, including the embryonic yolk sac, liver, spleen, and bone marrow. Before birth, hematopoiesis progresses through three stages: Mesoblastic (up to 2 months gestation), Hepatic (up to 7 months), and Myeloid (from 3 months onwards). Specific growth factors play crucial roles at different stages, affecting pluripotent stem cells, multipotent progenitor cells, and committed progenitor cells. The stages of hematopoietic cell development involve stem cell pool maintenance, differentiation, lineage selection, maturation, function, and cell death.
Thank you ma. I learnt that Haemopoiesis is the process by which blood cells are formed. STAGES OF BLOOD CELL FORMATION: Mesoblastic stage: 0-2 months yolk sac. Hepatic stage: 2-7 months - liver and spleen Myeloid stage: 5-9 months- bone marrow. The adult haemopoietic system originates in embryonic yolk sac and the blood cells production has a sequential migration from the liver, spleen and bone marrow as the embryo develops. Haemopoietic growth factors are cytokines, they are naturally occurring hormone like glycoprotein, they are required for the initiation and sustenance of the proliferation and differentiation of haemopoietic progenitor cells and the function of matured blood cells.
It was a very understanding session. I was able to know that Heamopoiesis is a process where by blood cells are formed from haemapioetic stem cells and also the stages of blood cell formation which starts from the Mesoblastic stage- occurs in the yolk sac from 0-2months Hepatic stage- occurs in the liver and spleen for 2-7 months Myeloid stage- occurs in the bone marrow for 5-9 months. Also I learnt about the haemapioetic growth factors which are known as naturally occurring hormones that are required for the initiation of the normal proliferation of the progenitor cells and how it functions in the maturation of blood cells with it's different stages and functions. I also learnt that they are two means by which blood cells passes from the bone marrow to the capillaries which are the DIAPEDESIS and HORNING.
Thank you Dr I like ur lectures,I understand that Hematopoiesis - the formation of blood cellular components - occurs during embryonic development and throughout adulthood to produce and replenish the blood system. Studying hematopoiesis can help scientists and clinicians to understand better the processes behind blood disorders and cancers.
Thank you for this wonderful lecture ma, in summary I have learnt the definition of haemopoiesis which is the process by which blood cells are formed. I now know the haemopoietic sites as well as blood cell formation before birth which under it there is the mesoblastic,hepatic and myeloid stage. I have also learnt about haemopoietic growth factors(HGF) which are naturally occurring hormone-like glycoproteins(cytokines). In addition I have learnt the organization of the haemopoietic system in which I picked a point that morphologically, haemopoietic stem cells are undifferentiated and resemble small lymphocytes. I also have learnt the stages in haemopoietic cell development and finally I have learnt about cellular release.
Thank you ma'am, for this educative lecture. In summary, I understood that Hemopoiesis is the process by which blood cells are formed (formation of blood) and can be called haematopoiesis. This further goes down to elements of blood which are 1. Red cells (Erythroblasts) 2. White cells (Leukocytes) 3. Platelets (thrombocytes) The process by which the above blood cells are formed is called Hematopoiesis This includes the following stages - Megaloblastic stage: blood cell formation occurs in the yolk sac and mesothelial layers of the placenta, this occurred for about two months of gestation - Hepatic stage: blood cell formation occurs in the liver and the spleen - Myeloid stage: This is simply the stage where the bone marrow is involved in the blood cell formation and production ( from third months up, the bone marrow becomes the principal site of RBCs and other cells N/B: > The bone marrow is the sole site of effective hematopoiesis in adult >when a child is below 5years, all the sites and bone in the system are involved in the blood cell production >By 18years, hematopoietic marrow is only found in vertebrae, ribs, skull, pelvis, and proximal epiphyses of the femora and humeri > Functions of the growth hormone - Regulation of normal haematopoiesis in the bone marrow - induction of cell viability and cell multiplication - prevention of apoptosis of haematopoietic progenitor cells - stimulation of phagocytosis of bacteria - enhancement of tumoridal activity of the macrophages Thank you ma'am
Thanks ma for this enlightenment series from this I have learnt what hematopoiesis is all about as the process of blood cells formation that's erythrocyte,leukocyte and thrombocytes, also learned the different stages of these cells formation as embryonic stage from 0-2month and it occurs in the yolk sac and at the endothelial layer of the placenta, the hepatic stage which occurs between 2-7months and it happens at the liver and spleen and the myeloid stage 3-9months and the bone marrow become the principal site and condition of extra medulary haemopoiesis on a condition of bone marrow dysfunction and the liver and spleen takes over again Also learnt the life span of different cells as RBCs 120days, platelets 7-10days and WBCs few hours and also the daily rate as 2.5 billions of RBCs, 2.5 billion platelets and 1.0 billion granulocytes per kg of body weight of the body Also learn the hemopoietic growth factor as naturally occurring hormone like glycoproteins (cytokines) required for initiations and sustainance of normal proliferations and differentiation of normal proginators cells and functions of mature blood cells like IL-1,TNF, IL-3,Gm-CSF,thromopoietin etc which act on difference site of the stem cells and there functions as they regulate normal homopoiesis in the bone marrow, prevention of apoptosis in normal proginator cells etc Thanks ma
Thank you ma'am for this wonderful teaching on haemopoiesis. At the course if listening keenly i learnt that haemopoiesis is the process by which blood cells are formed. That is; Erythrocytes Leukocytes Thrombocytes And thr haemopoietic sites are embryonic yolk sac, liver, spleen and bone marrow The haemopoietic growth factor are naturally occurring hormonal proteins necessary for initiation, differentiation of haemopioetic progenitor cells and normal functions of matured blood cells like the IL-1, TNF, IL-3, thrombopoietin etc which act on different stem cells
Thank you Ma In summary i learnt that Hemopoiesis is the process by which blood cells are formed. Adult haemopoiesis system originates in the embryonic yolk sac. Blood cell formation before birt, we have the 1.Mesoblastic stage 2.Hepatic stage 3.Myeloid stage Haemopoietic growth factor are naturally occurring hormone like glycoprotein (cytokines). Tyey initiate and sustain normal proliferation and differentiation of hemopoietic progenitor cells. Examples stem cell factor, Erythropoietic, Theombopoietic and Fit ligand. These growth factors are responsible for the regulation of normal haematopoiesis in the bone marrow, induction of cell viability and cell multiplication, prevention of apotosis of haematopoietic progenitor cells.
Good day ma I appreciate the time and effort you put in to explain the topic Haemopoiesis. I got to understand that Haemopoiesis is the process in which blood cells are being formed. Blood cell formation before birth involves three (3) which includes; mesoblastic stage, hepatic stage and myeloid stage. The mesoblastic stage,this begins in the yolk sac, leading to the liver where erythroblasts and myeloblasts develops. Hepatic stage,in this stage the liver and spleen are the site of blood cells production. The myeloid stage, the bone marrow is the site of blood cells production, producing red blood cells, various white blood cells types and platelets.
Thank you ma for this lecture Hematopoiesis is a process whereby blood cells are formed. Sites of adult hemopoietic system originates from embryonic yolk sac. Blood cell production migrates sequentially to the liver, spleen and bone marrow as the embryo develops. Blood cell formation before birth *Mesoblastic stage: blood cell formation takes place in the embryonic yolk sac and mesothelial layers of the placenta up to 2 month *Hepatic stage: Up to 7months And the production of blood cells takes place in the liver and spleen *Myeloid stage: from the 3rd month onwards the bone marrow gradually becomes the principal source of the RBC and other blood cells. The bike marrow Is the sole site of effective hematopoiesis in adult human beings
Thank you ma for this lecture In summary, I understood that haemopoiesis is the process by which blood cells are formed. Blood cell production migrates seuentially from the liver, spleen and bone marrow as the embryo develops. The bone marrow is the sole site of effective haematopoiesis in adult human beings. In normal adult its daily production amounts to about 2.5 billion red cells, 2.5 billion platelets and 1.0 billion granulocytes per kilogram of body weight. The site for haemopoiesis in fetus is yolk sac(0-2months), liver, spleen (2-7months) and bone marrow (5-9months). For infants is bone marrow (All bones). For adults is vertebrae, ribs, skull, sacrum and pelvis, proximal ends of femur and humen, sternum and illum. Haemopoiesiss Growth Factors (HGF) are naturally occurring hormone like glycoprotein required for initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells. HGF acts on different stages of bone marrow to bring about their functions. The haemopoietic system is a hierarchy of cells in which multipotent haemopoietic stem cells gives rise to lineage committed progenitor cells which divides to generate the maturing and mature blood cells. CD34 is the best known marker of human stem and progenitor cells. Haematopoietic stem cell is also called Haemocytoblast. Stem cells are capable of self renewal and differentiation when they divide and are responsible for producing all blood cells throughout life.
Thanks Dr, for this lecture on haemopoiesis. Take points Hemopoiesis/ haematopoiesis is the process of blood formation. Which involves elements of blood which are 1. Erythroblasts 2. Leukocytes 3. Thrombocytes The process involved in this blood cells formation is called Hematopoiesis There are three(3) stages of hematopoiesis: (i) Embryonic(Mesoblastic) Stage (ii) Hepatic (Foetal) Stage (iii) Myeloid Stage I. Megaloblastic stage: this stage occurs in the yolk sac and mesothelial layers of the placenta, which occurred for about two months of gestation II. Hepatic stage: this blood cell formation stage occurs in the liver and the spleen III. Myeloid stage: is the stage where the bone marrow is involved in the blood cell formation and production. Hematopoiesis Sites: In Fetus; the hematopoietic sites are primarily yolk sac, liver, spleen. In Infants; Bone marrow of all bones In Adult; Bone marrow of Rib, skull, pelvis, proximal end of femur and humeri. *The bone marrow is the sole site of effective hematopoiesis in adult *when a child is below 5years, all the sites and bone in the system are involved in the blood cell production *By 18years, hematopoietic marrow is only found in vertebra proximal epiphyses of the femora and humeri HEMOPOIETIC GROWTH FACTORS (HGF): this are naturally occurring hormones, that are required for initiation, sustainance of normal proliferation and differentiation of haemopoietic progenitor cells and formation of mature blood cells. They are like glycoproteins. Examples of HGF; IL-1, TNF, Stem cell factor, GM-CSF, erythropoietin, thrombopoietin, etc. Functions of the growth hormone includes; 1. Regulation of normal haematopoiesis in the bone marrow 2. induction of cell viability and cell multiplication 3. prevention of apoptosis of haematopoietic progenitor cells 4. stimulation of phagocytosis of bacteria 5. enhancement of tumoridal activity of the macrophages. In the Organization of haepoietic system, the haematopoietic system is an hierarchy of cells in which multipotent hemopoietic stem cells gives rise to lineage committed progenitor cells which divides and differentiate into maturing and mature blood cells. Renewal and Differentiation are the unique feature or characteristics of stem cells. Also CD34 is the beat known marker of human stem and progenitor cells. Blood cells pass from the bone marrow into the blood capillaries through the processes called- Homing and Diapedesis Homing is the process of hematopoietic cells moves to specific tissues or organs in the body. It involves a series of steps: i. Chemotaxis ii. Adhesion iii. Extravasation iv. Migration Diapedesis is the process or ability of hematopoietic cells squeezing through the pores of the capillary membrane.
Thank you so much for this informative lecture Ma. I learnt that haemopoiesis is the process of blood cell formation and it passes through three stages before birth. The mesoblastic stage in the yolk sac The hepatic stage in the liver and spleen and finally the myeloid stage in the bone marrow 😊
Thank you ma. In summary, I’ve been able to learn that ,Hematopoisesis is the process of blood formation from haematopoietic cells found in the bone marrow. It is a process where various type of cells are produced from haematopoietic stem cells. Haemopoietic sites where this takes place : 1. Embryonic yolk sac 2. Liver 3. Spleen 4. Bone marrow. Blood cell formation before birth: Mesoblastic stage- 2 months of gestation Hepatic stage- 7 months of gestation Myeloid stage- 3 months above. Haematopoietic growth factor -cytokines , they are required for initiation and sustenance of normal proliferation and differentiation of haematopoietic progenitor cells and the of mature blood cells Functions includes: 1. Regulation of normal haemapoiesis in the bone marrow 2. Induction of cell viability and cell multiplication 3. Prevention of apoptosis Apoptosis can be defined as program cell death . Huming is a process by which haematopoietic cells move to specific tissues or organs in the body Thank you very much ma.
Thank you mma for this lecture I learnt that the formation of blood cells are haemopoesis or hematopoesis I also learnt that blood cell formation of adults originate from the bone marrow, but at infant stage or before birth, blood cell formation takes place in the embryo (usually from 0-2 months) It's is termed as the hepatic stage of blood cell formation or production The stage where the bone marrow is the principal source of the red blood cell formation is the Myeloid stage Thank you mma
Thank you for this lecture ma. I'm conclusion, Haemopoiesis begins in the embryonic yolk sac but shifts to the liver, spleen, and bone marrow as the embryo grows. The bone marrow becomes the primary site of blood cell production after the fifth month of gestation, and it continues to be the sole site in adults. The process involves the formation of blood cells from haemopoietic stem cells, which differentiate into mature blood cells through various stages. Hematopoietic growth factors regulate this process by controlling cell growth, differentiation, and survival. The hematopoietic system consists of a hierarchy of cells, with multipotent stem cells giving rise to lineage-committed progenitor cells, which can either be myeloid or lymphoid. Myeloid lineage produces red blood cells and platelets, while lymphoid lineage generates immune cells. Blood cell migration from the bone marrow to the general circulation is tightly regulated, and apoptosis plays a crucial role in maintaining the balance of blood cells by disposing of unwanted or excess cells.
Thank you Dr Ify for this session Haemopoiesis Is the process by which blood cells are formed from the haemopoietic system. STAGES OF BLOOD CELL FORMATION Mesoblastic stage: 0-2 months-yolk sac and mesothelial layers of the placenta Hepatic Stage: 2-7 months - liver and spleen Myeloid Stage: 5-9 months - bone marrow Bone marrow is the site of effective haemopoiesis in adults with daily production of : 2.5 billion RBCs, 2.5 billion platelets, & 1.0 billion granulocytes per kg of body weight. LIFESPAN OF BLOOD CELLS RBCs -120daya Platelets-7-10days HAEMOPOIETIC GROWTH FACTORS IL-1, TNF acts in stromal cells Stem cell factor, fit ligand: acts on pluripotential stem cells IL-3, GM-CSF, IL-6, G-CSF, thrombopoietin: acts on multipotential progenitor cells G-CSF, M-CSF, IL-5, Erythpoietin: acts on committee progenitor cells. FUNCTIONS OF THE GROWTH FACTORS Regulation of normal haemopoiesis in the bone marrow. Stimulation of phagocytosis of bacteria. Induction of cell viability and cell multiplication ORGANIZATION OF HAEM Haemapoietic stem cells Pluripotent stem cells Myeloid and lymphoid progenitor cells RBCs, Megakaryocytes, basophils CFU, Eosinophils CFU, Granulocytes and monocytes CFU, B-cells, T-cells, and NK cells Neutrophils, monocytes and dentritic cell APOPTOSIS: Is the final stage in the life of blood cells.
Thanks Ma'am for the lecture. Haemopoiesis is the process by which blood cells are formed. Adult haemopoietic system originates in embryonic yolk sac. Blood cell production migrates sequentially to liver ,spleen and bone marrow as the embryo develops. There are 3 stages in blood cell formation before birth. 1) Mesoblastic stage: occurs in the yolk sac and mesothelial layers of the placenta. It occurs in about 0-2months of gestation. 2) Hepatic stage: It occurs in the liver and spleen, 2months ,up to 7months. 3) Myeloid stage: Occurs in the bone marrow from the third month upward and last month in the bone marrow exclusively. In adult , haemopoiesis occurs in the vertebrae,ribs,skull,sacrum and pelvis, proximal ends of femur and humeri,sternum and ileum. There are several growth factors that stimulates blood cell formation through proliferation and differentiation of haemopoietic progenitor cells and the function of mature blood cells.These includes; IL-1,TNF,stem cell factor,fit ligand,IL-3,GM- CSF,IL-6 ,G- CSF, thrombopoietin.etc The haemopoietic system is a hierarchy of cells inwhich multipotent haemopoietic stem cells give rise to lineage committed progenitor cells ,which divides to generate the maturing and mature blood cells. CD34 is the best known marker of human stem and progenitor cells.Stem cells are capable of self renewal and differentiation when they divide and are responsible for producing all blood cells throughout life. There are various stages in haemopoietic cell development, these include; stem cell pool, differentiation,lineage selection, maturation, function and cell death(apoptosis).
Thank you very much Ma. In summary haemopoiesis is the process by which blood cells are formed ,it is also know as haematopoiesis. Example of site of haemopoiesis in fetus include : yolk sac (0-2months), liver, spleen( 2-7months), Bone marrow (5-9months). Example of site haemopoiesis in infants is “bone marrow” Example of site of haemopoiesis in adults includes : vertebrae, ribs ,skull, sacrum,pelvis, sternum. Haematopoiesis involves haemopoietic growth factors (HGF) are naturally occurring hormone like glycoproteins (cytokines) required for initiation and substance of normal proliferation and differentiation of haemopoietic progenitor cells and function of mature blood cells , examples include: TNF, IL, GM-CSF, GM-CSF, Stem cell factor ,IL-5, M-CSF etc. Blood cells formed from Hematopoiesis pass from the bone marrow into the blood capillaries through two processes known as Homing and Diapedesis. The final stage in the life of a blood cell is death and disposal by apoptosis.
Thank you ma'am. In summary, I learnt that haemopoiesis is the process by which blood cells are formed. I also learnt the different haemopoietic sites such as in adult is vertebrae ribs,skull, sacrum &pelvis and proximal ends of femur and humeri, sternum, illum, then in fetus (0-2months) yolk sac, 2-7months is liver, spleen,5-9months is bone marrow also infants is in the bone marrow . I understood that haemopoietic growth factors are naturally occurring hormone like glycoproteins(cytokines) required for initiation, substance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of mature blood cells . Also, I learnt the functions of haemopoietic growth factors which includes regulations of normal haemopoiesis in the bone marrow, induction of cell viability and cell multiplication, prevention of apoptosis of haemopoietic progenitor cells and stimulation of phagocytosis of bacteria etc. The haemopoietic system is a hierarchy of cells in which multipotent haemopoietic stem cells give rise to lineage- committed progenitor cells which divide to form mature blood cells. Also, haemopoietic stem cells are undifferentiated and resemble small lymphocytes, CD34 is the best known marker of human stem and progenitor cells. Stem cells are capable of self renewal and differentiation when they divide and are responsible for producing all blood cells throughout life. I also understood that in division and differentiation,the pluripotent cells mature to multipotent mixed myeloid (CFU-GEMM)& lymphoid progenitor cells, further division & maturation to committed cells(CFU-GME) and then the uncommitted lymphoid stem cells differentiate to B-cells,T- cells and NK cells. Lastly, I learnt that in cellular release, cell migration from bone marrow to the general circulation is tightly regulated by a complex interplay of signal from the bone marrow micro environment circulating growth factors and cytokines. Thanks once more ma for this amazing lecture.
Dr ify thank you, from this class i was made to understand what haematopiesis. Haematopiesis is the process by which blood cells are formed. I also i understand the site for haematopiesis., which is th main site for haematopiesis (the formation of blood cells) is the bone marrow, which is found in the center of most bones. The bone marrow is a spongy tissue that contains stem cells, which are the cells that can develop into different types of blood cells. In adults, the primary site of haematopiesis is the bone marrow of the pelvis, sternum, and vertebrae. The bone marrow produces red blood cells, white blood cells, and platelets. It also produces stem cells. I also understand haemopoietic growth factor and it functions. And we haemopoietic growth factor are naturally occurring hormone like glycoprotein (cytokine) required for initiation and maintenance of normal proliferation and dissociation of haemopoietic progenitor cell and formation of mature blood cells. Functions include they involve in preventing apoptosis, regulations of normal haematopiesis in the bone marrow etc. Stages in haemopoietic development include 1. Haemocytoblast - This is the stem cell that can become any type of blood cell. It divides to produce daughter cells that are committed to a specific lineage. 2. Proerythroblast - This is the first committed cell of the red blood cell lineage. It undergoes a process called enucleation, where it loses its nucleus. 3. Reticulocyte - This is a mature red blood cell that has not yet lost all of its organelles.
Thank you ma, I’m summary Haemopoiesis is the process of the formation of blood cells. Haematopoietic sites includes embryonic yolk sac, liver, spleen and bone marrow. Stages of haemopoiesis are mesoblastic and hepatic stages. Haematopoiesis growth factors are naturally occurring hormones like glycoprotein required for initiations and maintenance of normal proliferation and dissociation of haemopoietic progenitor cells and formation of mature blood cells. Their functions include:- - Involvement in cell multiplication and viability - Prevent apoptosis of progenitor cells - Regulate normal haemopoiesis in bone marrow.
Thank you ma for this lecture, i have learnt that haematopoesis is the process of blood formation and the site of formation in adults is the bone marrow.
Thank you Doctor I learnt that haemopoeisis is the formation of blood cells which includes erythrocyte, leucocyte and platelet I also learned that embryonic yolk sac is where adult haemopoeitic system origin ate
Thank you for the lecture, madam. Below, I have shared some important points on the topic of Hematopoiesis. Hematopoiesis is the process of forming blood cells in the body, which occurs during embryonic development and throughout adulthood. It takes place in organs and tissues such as the bone marrow, liver, and spleen. The three main types of blood cells are red blood cells, white blood cells, and platelets. During embryonic development, Hematopoiesis produces only red blood cells, which provide developing organs with oxygen. At this stage, the yolk sac controls hematopoiesis until the placenta is fully developed. As the embryo continues to develop, the hematopoietic process moves to the liver, spleen, and bone marrow, and begins to produce other types of blood cells. In adults, hematopoiesis of red blood cells and platelets occurs primarily in the bone marrow. However, in infants and children, it may also occur in the spleen and liver. Haemopoietic growth factors play a crucial role in regulating the differentiation and proliferation of particular progenitor cells and the function of mature red blood cells. These growth factors include IL-1, IL-3, stem cell factor, GM-CSF, etc. They help stimulate phagocytosis of bacteria, enhance tumoridal activity of macrophages, and aid in the regulation of normal hematopoiesis in the bone marrow. Blood cells pass from the bone marrow into the blood capillaries through two processes - Homing and Diapedesis. Homing refers to the process by which hematopoietic cells move to specific tissues or organs in the body, while Diapedesis is the ability of cells to squeeze through the pores of the capillary membrane. Studying hematopoiesis helps scientists and clinicians to understand the processes behind blood disorders and cancers.
Thank you ma, I learnt that haematopoiesis is the formation of cells found in the blood,and that the Sites for blood cell formation before birth has 3 stages. The Mesoblastic stage ( occurs at about 0 - 2months of gestation in the yolk sac), Hepatic stage ( occurs from 2 - 7 months in the liver & spleen) & Myeloid stage ( occurs from 5 - 9 months in Bone marrow). When a child is below 5yrs, all the bones in the system are involved in hematopoiesis. By the age of 18yrs it is restricted in the vertebrae, ribs, skull, pelvis & proximal epiphyses of the femora & humeri. Thank you
Thank you ma, I have understood that haemopoiesis is the process by which blood cells are formed. Adult haemopoietic system originates in the embryonic yolk sac. Blood cell formation before birth are mesoblastic stage(up to 2month), hepatic stage(up to 7month), and myeloid stage(third month onwards). Site of haemopoiesis in infant is bone marrow, in adults is vetebrae, ribs,skull,sacrum, pelvis etc. Haemopoietic growth factors are naturally occurring hormone required for initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of matured blood cells. Functions of these growth factors include; - Regulation of normal haematopoiesis in the bone marrow - Induction of cell viability - Prevention of apoptosis - Stimulation of phagocytosis Haematopoietic system is a hierarchy of cells in which multipotent haemopoietic stem cells give rise to lineage committed progenitor cells which divide to generate the maturing and matured blood cells. Blood cells pass from the bone marrow into the blood capillaries through homing and Diapedesis.
Thanks ma for the lecture, Haemopoiesis is the process by which blood cells are formed, before birthday the blood cell formation occurs in three stages which are; mesoblastic stage which occurs in the yolk sac and mesothelial layers of the placenta, it takes place about 0-2 months of the gestation. Hepatic stage where the liver and spleen take up from the previous stage, it take place from 2-7months, Myeloid stage from 5-8 months upwards the bone marrow gradually Because the principal source of red blood cells and other blood cells, bone marrow is the only site of effective hematopoiesis in adult, Hematopoietic growth factors are natural occuring hormones like glycoproteins they functions include indication of cell viability and cell multiplication, prevention of apoptosis of haemopotic progenitor cell, stimulation of phagocytosis of Bacteria, the stages of haemopotic cell development ranges from stem pool where it gives rise to renewal and differentiate into linage committed cells, to Myeloid stage and lymphoid linage
Thank you ma'am In summary haemopoiesis also known as haematopoiesis is defined as the process by which blood cells are formed. The formed blood cells are 1. RBCs - Erythrocytes 2. WBCs - Leukocytes 3. Platelets - Thrombocytes HAEMOPOIETIC SITES - Adult haemopoietic system originate in embryonic yolk sac. In the embryonic stage blood cells are formed in the yolk sac - Blood cell production migrates sequentially to the liver spleen and bone marrow as the embryo grows. 1. Mesoblastic stage:(0- 2months) formation of blood cells occurs in the yolk sac and mesothelial layers of the placenta 2. Hepatic stage: 1- upto 7 months the liver form the blood cells Spleen also form the blood cells 3. Myeloid stage: from third month onward the bone marrow becomes the principal source of the RBCs and other blood cells 4. Last month: bone marrow exclusively - The bone marrow is the sole site of hematopoiesis in adult human beings In normal adult the daily production amount is about 2.5 billion RBCs, 2.5 billion platelets, and 1.0 billion granulocytes per kg of body weight
Thanks ma. I learnt that haemopoiesis is the process by which blood are formed and is also process of blood cell formation, begins in embryonic sacs like the yolk sac and later involves the liver, spleen and bone marrow. There are different sites of Haemopoiesis which are Fetus:0-2 months ( Yolk sac) 2-7 months (liver, spleen) 5-9 months (bone marrow) Infants: Bone marrow (All bones) Adults: Vertebrae, ribs, skull sacrum, pelvis, proximal ends of femur and humeri, sternum.
Thank you ma for the lecture..I got to understand that: Haemopoiesis is the process by which blood cells are formed Also the haempoietic sites: Adult haemopoietic system originates in the embryonic yolk sac Blood cell production migrates sequentially to the liver,spleen and bone marrow as the embryo develops. Also blood cell formation before birth includes mesoblastic stage,hepatic stage and myeloid stage The bone marrow is the sole site of effective haematopoiesis in adult human beings. Sites of haemopoiesis Fetus:0-2 months (yolk sac) 2-7 months (liver, spleen) 5-9 months (bone marrow) Infants:bone marrow (all bones ) Adults:vertebrae,ribs,skull,sacrum and pelvis ,proximal ends of femur and humeri,sternum,ileum . Also ,haemopoietic growth factors which are cytokines requires for the initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of mature red blood cells. Also the HPGs acts on: 1 stromal cells 2 pluripotential progenitor cells 3 act on multi potential progenitor cells 4 act on committed progenitor cells etc . Functions of HPGs 1 regulation of normal haematopoiesis in the bone marrow 2 induction of cell viability and cell multiplication 3 prevention of apoptosis of haemopoietic progenitor cells 4 stimulation of phagocytosis of bacteria etc . In summary,the end product of haemopoietic cell development are cells that are highly specialized for their different functions in the body .etc
Thanks ma for this awesome lecture. First I learnt that Hemopoiesis is the formation of blood cells. Blood cell formation before birth which is ; 1 mesoblastic stage which occur in the yolk sac, 2. The Hepatic stage which occur in the liver , spleen (up to 7month). 3. The myeloid stage which occur in the bone marrow (from th 3rd month). I learnt that the bone marrow is the sole site of effective haematopoiesis in adult Humm being.. I also learnt site for haematopoiesis. For infant - bone marrow For adults - the vetibrate, ribs skull, sternum, illeum & pelvis. I also learnt that haematopoiestic growth factor act on ; 1. Stromal cells e.g IL-1, TNF. 2. Pluripotential stem cell e.g stem cell factor, ligand. 3. Act on converted progenitor cells e.g G- CSF , M -CFS . Function of Growth factor. 1 Regulations of normal haematopoiesis. 2. Induction of cell viability and cell multiplication etc. To round it up the final stage In the life of blood is death and disposal by apoptosis.
Thank you ma In summary , I learnt that haemopoiesis is the process by which blood cells are formed . And I also learnt about the sites of haemopoiesis which are ;the yolk sac,liver,spleen, and bone marrow. I also learnt about the blood cell formation before birth which are ; Mesoblastic stage ,hepatic stage and myeloid stage . And also I learnt about the haemopoietic Growth factors which are naturally occurring hormone-like glycoproteins I also learnt about their functions and also the stages of haemopoietic cell development.
Thank you Dr I learnt that blood passes from the bone marrow into the blood capillaries through the homing and diapedesis processes. I also learnt the stages in haemopoietic cell divisions
A really insightful lecture ma, To summarize, I’d start by defining hemopoiesis which is the process by which blood cells are formed. This hemopoiesis occurs in different sites in the body but this depends on the state of development of the individual. This site of blood cell production migrated from the yolk sac and mesothelial layer of the placenta of the fetus at 2 months, to the liver and spleen of said fetus at 7 months. During the last month, it becomes bone marrow exclamation. The bone marrow is the site of effective hematopoiesis in adult humans. The hemapoietically active marrow regresses after birth until late adolescence after which time it is focused on the marrow of lower skull, vertebrae,shoulder and pelvic girdles,sternum and ribs. Hematopoietic growth factors are naturally occurring hormone like glycoproteins which are required for the sustenance and initiation of normal proliferation and differentiation of haematopoietic progenitor cells and functions of mature blood cells. Examples of these growth factors in IL-1, Tumor necrosis Factor, IL-3, stem cell factor, fit ligand, IL-6, G-CSF,M-CSF,IL-5, etc. Their functions include -Stimulation of phagocytosis of bacteria -Enhancement of tumoridal activity of macrophages -prevention of hematopoietic progenitor cells -induction of cell viability and manipulation -regulation of normal hematopoiesis in bone marrow. The stages of development for these hematopoietic cells begin from stem cells which have the ability of self renewal and then differentiate in to lineage committed progenitor cells which then mature and carry out their functions. After this, what comes next is cell death. The end product of hematopoietic cell development is to produce cells which are highly specialized for their function in the body.
Thank you so much ma. I have gotten knowledge from this topic haempoiesis which is the formation of blood cell, where adult is originate from yolk sac. The blood cell migrate in the liver and the spleen and bone marrow. Stages of blood cell formation before birth which includes; 1.mesoblastic stage:yolk sac 2.hepatic stage:blood cell is form in the live and spleen 3:myeloid stage:bone borrow Blood cell formation after birth ; I.the bone marrow is form in 5years. II.by age of 18 years which is found in vertebrae, ribs ,skull etc. Growth factor of haemopoietic which can be called cytokines and it is natural which involves in proliferation and differentiation and also involve function of mature blood cells. Organisation of haemopoietic systems: which is hierarchy of cells in which multipoint haemopoietic system which give rise to lineage committed progenitor cell. Cellular release: this involves homing and diapedesis Lastly you talk about cell death is called apoptosis which is removal of unwanted cell and this processes that occurs doesn't release lysosomal or granule come contents that could cause an inflammatory reaction
Thank you Ma, for this comprehensive lecture. At the end of this lecture I learnt that; Haemopoiesis is the process in which blood cells are formed. Site of Haemopoiesis in adult is embryonic yolk sac. Blood cell formation before birth are of 3 stages; 1. Mesoblastic stage: this occurs in the yolk sac and mesothelial layers of the placenta. It occurs about 0-2 month of gestation. 2. Hepatic stage: The liver and spleen takes up from the preceding stage. This occurs 2-7 months 3. Myeloid stage: in this stage, the bone marrow gradually becomes the principal site of RBCs and other blood cells. This occurs from 7 months upwards. I also learnt that Haematopoietic growth factor are naturally occurring hormone-like glycoprotein(cytokines). They initiate and sustain normal proliferation and differentiation of hemopoietic progenitor cells. Examples Stem cell factor, Fit Ligand, Erythropoietin, thrombopoietin. These growth factors are responsible for the regulation of normal Haematopoiesis in the bone marrow, induction of cell viability and cell multiplication, prevention of apotosis of haematopoietic progenitor cells, Stimulation of phagocytosis of bacteria, enhancement of tumoridal activity of macrophages.
Thank you ma for this lecture In summary, The process by which blood cells are formed is called haematopoiesis Adult haemapoietic system oroginates in the embryonic yolk sac, blood cell production migrates sequentially through the liver, spleen and bone marrow as the embryo develps Blood cells development before birth includes; Mesoblastic stage Hepatic stage Myeloid stage Blood cells synthesis in the final month is entirely in the bone marrow Haematopoietic growth factor are naturally occuring hormone like glycoproteins necessary for the beginning snd sustenance of appropriate proliferation Growth factor is important in the regulation of normal haematopoiesis in bone marrow among others
Thank you MA, for this wonderful lecture. I learnt the following at the end of the lecture: A. HAEMOPOIESIS: It is also called haematopoiesis. It's the process by which blood cells are formed(red blood cells, white blood cells and platelets). B. SITES OF HAEMOPOIESIS *FETUS: 0-2months(yolk sac) 2-7months(liver, spleen) 5-9months(Bone marrow) *INFANTS: Bone marrow (all bones) *ADULTS: Vetebrae, ribs, sternum, illeum, sacrum and pelvis, proximal end of femur and humeri. C. HAEMOPOIETIC GROWTH FACTORS: They are naturally occurring hormone-like glycoproteins(cytokines) required for initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of mature blood cells. D. FUNCTIONS OF HAEMOPOIETIC GROWTH FACTORS 1. Regulation of normal haemopoiesis in the bone marrow. 2. Induction of cell viability and cell multiplication. 3. Prevention of apoptosis of haemopoietic progenitor cells 4. Stimulation of phagpcytosis of bacteria 5. Enhancement of tumoridal activity of macrophages. E. STEPS IN HAEMOPOIETIC CWLL DEVELOPMENT Haemopoietic cell development starts from the stem cell pool which is capable of cell renewal and leads to differentiation and to lineage selection (myeloid lineage or lymphoid lineage) they undergo maturation, and perform their functions in the body(red blood cells which carries oxygen, white cells for immunity and platelet for coagulation) the encounter cell death(apoptosis), and last stage is removal from the body.
God bless u Dr. What l learnt is that in the process of haematopoietic ontogeny, I describes the development of various blood cells from pluripotent stem cells, and uncommitted lymphoid stem cells (SCs) differentiate into B, T and NK cells. This differentiation process is a crucial aspect of hematopoietic ontogeny, where lymphoid progenitor cells give rise to these specific types of immune cells.
HAEMOPOIESIS Tank u ma'am for the worderful lecture, i actually learned about haemopoiesis which is simple mean the process in which blood cell are formed. There are three elements of blood which are Red blood cells, White blood cells, Platelets . The process in which this element of blood are formed is called Haemopoiesis. Site of Haemopoiesis are Adult haemopoiesis originates in embryonic yolk sac. Adult blood are produced in the bone marrow. The is special migration bfrom the yolk sac to the liver, spleen and bone marrow bas the embryo develop . Blood cell formation before birth. Mesoblastic stage this made of yolk sac and mesothelial layer of the placenta . From two months nof gestation the liver and the spleen take up the work of blood formation. Hepatic stages. This is up to 7months . From 5months we have the bone marrow for the production of blood cell Myeloid stage.this is a stage in which the bone marrow is involved in the production of blood cell. The bone marrow is the site of haemopoiesis in adult but when the bone marrow compromise it result to extra medullary
Thank you Ma for this interesting Lecture I learnt that Haemopoiesis is the process of blood cell formation and it progresses through three stages before birth, the mesoblastic stage in the yolk sac, followed by the hepatic stage in the liver and spleen, and finally the myeloid stage in the bone marrow. At birth, the bone marrow becomes the primary site for hematopoiesis in adults. Haemopoietic growth factors (HGF) regulate this process, promoting cell viability, multiplication, and preventing apoptosis. Blood cells develop from stem cells into myeloid and lymphoid lineages, yielding various cell types. They pass from the bone marrow into the bloodstream via homing and diapedesis, involving chemotaxis, adhesion, extravasation, and migration.
Thank you for this great lecture. In summary, have learnt that, HAEMOPOIESIS Is the process of formation of blood cell. There is a balance maintained between cell renewal, terminal differentiation, cell death and migration. THREE STAGES OF BLOOD CELL FORMATION before birth; 1.Mesoblastic stage: (0-2 months-yolk sac) and mesothelial layers of the placenta. 2.Hepatic Stage: 2-7 months - liver& spleen.) 3. Myeloid Stage: 5-9 months(bone marrow which is the principal source of RBCS. There are different sites of hematopoiesis. stem cells are capable of self renewal. Stem cell gives rise to linage selection ,differentiated into myeloid and lymphoid linage which are involved inT,B lymphocyte, and NK cells.goes to maturation and carry out their functions and undergo apoptosis ( programs cell death).
Interesting ton know
Thank you
Thank you Dr. You make studying Haematology easy
Thank you ma,for this educative lecture 👏
Educating lecture thank u ma
What a knowledgeable lecture ma
Thank you ma for a very explanatory lecture
Interesting lecture ma’am
Thank you ma
I have learnt about the definition of haemopoiesis and also the growth factors and also explain it’s function
HAEMOPOIESIS (HAEMATOPOIESIS)
Thank you ma'am for this excellent lesson delivery. I've discovered that HAEMOPOIESIS is the process by which blood cells are created.
This process may alternatively be named HAEMATOPOIESIS.
The produced constituents of blood include; 1. Red cells(erythrocytes)
2. White cells( leucocytes)
3. Platelets (thrombocytes).
HAEMATOPOIESTIC SITES
Adult's haematopoietic system begins in the embryonic yolk sac.
Blood cells production move progressively in the liver, spleen and bone marrow as the embryo grows.
Blood cell development before birth has many phases which include:
1. Mesoblastic stage- it takes place in the yolk sac and mesothelial layers of the placenta from zero to 2 months.
2. Hepatic stage- during this stage, blood cells are created in the liver and also the spleen and this might vary up to 7 months.
3. Myeloid stage- from the third month Upwards, the bone marrow increasingly becomes the major supplier of RBCs and other blood cells.
Blood cells synthesis in the final month is entirely in the bone marrow.
The bone marrow bis the single location of efficient haematopoiesis in mature human beings.
In normal people, its daily output amounts to roughly 2.5 billion red cells and platelets with 1.0 billion granulocytes per kilogram of body weight.
Haematopoietically active (red) marrow regresses after birth untill late adolescence at which time it is localized in the lower skull, vertebrae, shoulder and pelvic girdles, ribs and sternum.
HAEMATOPOIETIC GROWTH FACTOR
These are naturally occurring hormone-like glycoproteins (cytokines) necessary for the beginning and sustenance of appropriate proliferation And differentiation of haematopoietic progenitor cells and the function of adult blood cells. They act on stromal cells : IL-1, TNF.
FUNCTIONS OF GROWTH FACTOR
1. Regulation of normal haematopoiesis in bone marrow
2. Induction of vell viability and cell proliferation.
3. Prevention of apoptosis of haematopoietic progenitor cells.
4. Stimulation of phagocytosis of bacteria
5. Enhancement of tumoridal activity of macrophages.
The haematopoietic system is thus arranged in a system of hierarchy of cells in which multi potent haematopoietic stem cells will give birth to lineage committed progenitor cells which divide to form the maturing and mature blood cells.
Morphologically, haematopoietic stem cells are undifferentiated and resemble tiny lymphocytes.
CD34 is the best recognized marker of human stem and progenitor cells.
Stem cells are capable of self renewal and differentiation. When they divide, they are responsible for creating all blood cells throughout life.
While in steady state, stem cells divide only 50% of the daughter cells or average differentiate. The remaining 50% don't differentiate, but retain stem cell levels.
CELLULAR RELEASE
Cell migration from bone marrow to general circulation is entirely controlled by a complex interplay of signals from the bone marrow micro environment, circulating growth factors and cytokines and feedback mechanism that account for balanced generation of various blood cells.
Cellular migration is under the control of a class of tiny cytokines called chemokines.
To escape the bone marrow, the reticulocytes rely on a pressure gradient across the membrane to force it through the porosity.
Blood cells travel from the bone marrow into the blood capillaries by these processes; HOMING and DIAPEDESIS.
Homing is a process by which haemopoietic cells travel to certain tissues or organs in yhe body.
Homing process contains a number of phases and they include;
1. Chemotaxis - cells follow gradients of signalling chemicals like chemokines.
2. Adhesion - capacity of cells to connect to endothelial cells that line the blood arteries
3. Extravasation - the capacity of cells to squeeze through the spaces between endothelial cells then move.
CELL DEATH (APOPTOSIS)
The ultimate step in the life of a blood cell is death and disposal via apoptosis.
Apoptotic cell death is a process for disposing of undesirable or surplus cells. It occurs commonly in biological systems.
It ensures the dispersion of cells without releasing any lysosomal or granule material that might provoke an inflammatory response.
Apoptosis comprises a complicated set of processes that end in the activation of the caspase proteases, fragmentation of DNA and phagocytosis of apoptotic particles by macrophages.
NOTE:
1. Stem cells are the most significant cells in haematopoietic cell creation.
2. They are ultimately responsible for rebuilding haemopoiesis after injury to the haematopoietic system by myelotoxic chemotherapy or after stem cell transplantations. This is performed via stem cell division, creating new stem cells to sustain the stem cell pool and developing cells that are the progenitor cells of each of the blood cells.
3. The final products of haematopoietic cell development are cells that are highly specialized for the varied tasks in the body.
Thank you ma for this informative lecture I learnt that haematopoesis is the process of blood formation
Thank you Dr. for making this topic explanatory.
Adult haemopoiec system originates from the embryonic yolk sac.
-Blood cell before birth (Mesoblastic stage)
-Hepatic stage (liver and spleen)
-Myeloid(bone marrow becomes the site for blood cell production)
The bone marrow is the sole site of effective haematopoesis in Adults. About 2.5 billion RBC, 2.5 billion platelets, and 1.0 billion granulocytes per body kilogram.
Before age 5, all the bones in the body are involved in blood production.
Summary of sites of haemopoiesis-
For Fetus:
0-2 months, yolk sac)
2-7 (liver and spleen)
5-7 (Bone marrow)
For Infants:
Bone marrow (all the bones are involved)
For adults:
Sites like Vertebra, femur, allium,Sacrum, humerus, Skull.
HGF- Haematopoetic growth factors
Thank you Ma
This lecture has helped me to understand the various sites of haemopoiesis and what haemopoietic growth factors are❤
Thank you so much Dr for this great lecture. I learnt that the function of the growth factor include the regulation of normal haematopoiesis in the bone marrow.
Stimulation of phagocytosis of bacteria and induction of cell viability and cell multiplication.
I also learned that the organisation of haem include
Haematopoietic stem cells, pluripotent stem cells, myeloid and lymphoid progenitor cells.
Thank you so much Ma
Thank you so much Dr, what a great lecture. HAEMOPOIESIS
Is the process by which blood cells are formed from the haemopoietic system.
STAGES OF BLOOD CELL FORMATION
Mesoblastic stage: 0-2 months-yolk sac and mesothelial layers of the placenta
Hepatic Stage: 2-7 months - liver and spleen
Myeloid Stage: 5-9 months - bone marrow
Bone marrow is the site of effective haemopoiesis in adults with daily production of : 2.5 billion RBCs, 2.5 billion platelets, & 1.0 billion granulocytes per kg of body weight.
LIFESPAN OF BLOOD CELLS
RBCs -120daya
Platelets-7-10days
HAEMOPOIETIC GROWTH FACTORS
IL-1, TNF acts in stromal cells
Stem cell factor, fit ligand: acts on pluripotential stem cells
IL-3, GM-CSF, IL-6, G-CSF, thrombopoietin: acts on multipotential progenitor cells
G-CSF, M-CSF, IL-5, Erythpoietin: acts on committee progenitor cells.
FUNCTIONS OF THE GROWTH FACTORS
Regulation of normal haemopoiesis in the bone marrow.
Stimulation of phagocytosis of bacteria.
Induction of cell viability and cell multiplication
ORGANIZATION OF HAEM
Haemapoietic stem cells
Pluripotent stem cells
Myeloid and lymphoid progenitor cells
RBCs, Megakaryocytes, basophils CFU, Eosinophils CFU, Granulocytes and monocytes CFU, B-cells, T-cells, and NK cells
Neutrophils, monocytes and dentritic cell
APOPTOSIS: Is the final stage in the life of blood cells.
Thank you Ma’am for this wonderful lecture.
HAEMOPOIESIS
Is the process by which blood cells are formed from the haemopoietic system.
STAGES OF BLOOD CELL FORMATION
Mesoblastic stage: 0-2 months-yolk sac and mesothelial layers of the placenta
Hepatic Stage: 2-7 months - liver and spleen
Myeloid Stage: 5-9 months - bone marrow
Bone marrow is the site of effective haemopoiesis in adults with daily production of : 2.5 billion RBCs, 2.5 billion platelets, & 1.0 billion granulocytes per kg of body weight.
LIFESPAN OF BLOOD CELLS
RBCs -120daya
Platelets-7-10days
HAEMOPOIETIC GROWTH FACTORS
IL-1, TNF acts in stromal cells
Stem cell factor, fit ligand: acts on pluripotential stem cells
IL-3, GM-CSF, IL-6, G-CSF, thrombopoietin: acts on multipotential progenitor cells
G-CSF, M-CSF, IL-5, Erythpoietin: acts on committee progenitor cells.
FUNCTIONS OF THE GROWTH FACTORS
Regulation of normal haemopoiesis in the bone marrow.
Stimulation of phagocytosis of bacteria.
Induction of cell viability and cell multiplication
ORGANIZATION OF HAEM
Haemapoietic stem cells
Pluripotent stem cells
Myeloid and lymphoid progenitor cells
RBCs, Megakaryocytes, basophils CFU, Eosinophils CFU, Granulocytes and monocytes CFU, B-cells, T-cells, and NK cells
Neutrophils, monocytes and dentritic cell
APOPTOSIS: Is the final stage in the life of blood cells.
Thank you ma for this interesting lecture.
Haemopoiesis is a process by which blood cells are formed. Adult haemopoietic system originates in the embryonic yolk sac. Blood cell production migrates sequential to the liver, spleen and bone marrow as the embryo develops.
Blood cell formation has three stage:
1. Mesoblastic stage - occurs in the yolk sac and mesothelial Layers of the placenta.
2. Hepatic stage - occurs in the liver and spleen.
3. Myeloid stage - occurs in the bone marrow.
Haemopoietic growth factor are naturally occurring like glycoproteins. They are required for initiation and sustainance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of mature blood cells.
Functions of Growth factor includes:
1. Regulation of normal haemotopoiesis in the bone marrow.
2. Induction of cell viability and cell multiplication.
3.prevention of apoptosis of haemopoietic progenitor cells.
4. Stimulation of phagocytosis of bacteria.
5. Enhancement of fumoridal activity of macrophages.
Thank you for this enlightening lecture on Haemopoiesis
Here's my summary;
Haemopoiesis Also known as haematopoiesis is the process by which blood cells are formed.
The formed blood cells are
Red Blood cells (Erythrocytes)
White blood cells( leukocytes)
PlateletsThrombocytes)
Sites of Haemopoiesis
Fetus:
0-2 months_Yolk sac
2-7 months _Liver, spleen
5-9 months _ Bome marrow
Infants
Bone marrow
Adults
Vertebrae, ribs, skull, sacrum, pelvis, proximal ends of femur and humeri,sternum and ileum.
Haemopoetic Growth Factors
These are naturally occurring hormone-like glycoproteins (cytokines) that are required for the initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells and the formation of mature blood cells.
Examples of such factors are as follows: interleukin-1, Tumor Necrosis Factor, interleukin-3, GM-CSF, interleukin-6, interleukin-5 etc
Functions of the Growth factors
Formation of normal Haemopoiesis in the bone marrow
Induction of cell viability and cell multiplication
Prevention of apoptosis of haemopoietic progenitor stem cells
Enhancement of tumoridal activity of macrophages
Organisation of haemopoietic system
The haemopoietic system is a hierarchy of cells in which multipotent haemopoietic stem cells gives rise to lineage-committed progenitor cells, which divides to generate the maturing and the matured blood cells.
Morphological, Haemopoietic stem cells are undifferentiated and resembles Small lymphocytes.
CD34 is the best known marker of human stem and progenitor cells.
Haemopoietic Ontogeny
Through division and differentiation, the pluripotent cells mature to multipotent mixed myeloid and lymphoid progenitor cells.
Further division and maturation gives rise to committed cells
The uncommitted lymphoid stem cells differentiate to B lymphocytes, T lymphocytes and Natural Killer cells
Cellular Release
Cell migration from bone marrow to the general circulation is tightly regulated by a complex interplay of signals from the bone marrow micro environment, circulatory growth factors and cytokines and feedbacks mechanisms that accounts for balanced production of different blood cells
To leave the marrow, the reticulocyte depends on a pressure gradient across the membrane to drive it through the pore
The processes involved includes;
Honing and diapedesis
Thank you, Ma, for this important lecture. In summary, i learnt that HAEMOPOIESIS is the process by which blood cells are formed from the haemopoietic system.
STAGES OF BLOOD CELL FORMATION
Mesoblastic stage: 0-2 months-yolk sac and mesothelial layers of the placenta
Hepatic Stage: 2-7 months - liver and spleen
Myeloid Stage: 5-9 months - bone marrow
Bone marrow is the site of effective haemopoiesis in adults with daily production of : 2.5 billion RBCs, 2.5 billion platelets, & 1.0 billion granulocytes per kg of body weight.
LIFESPAN OF BLOOD CELLS
RBCs -120days
Platelets-7-10days
HAEMOPOIETIC GROWTH FACTORS
IL-1, TNF acts in stromal cells
Stem cell factor, fit ligand: acts on pluripotential stem cells
IL-3, GM-CSF, IL-6, G-CSF, thrombopoietin: acts on multipotential progenitor cells
G-CSF, M-CSF, IL-5, Erythpoietin: acts on committee progenitor cells.
FUNCTIONS OF THE GROWTH FACTORS
Regulation of normal haemopoiesis in the bone marrow.
Stimulation of phagocytosis of bacteria.
Induction of cell viability and cell multiplication.
ORGANIZATION OF HAEM
Haemapoietic stem cells
Pluripotent stem cells
Myeloid and lymphoid progenitor cells
RBCs, Megakaryocytes, basophils CFU, Eosinophils CFU, Granulocytes and monocytes CFU, B-cells, T-cells, and NK cells
Neutrophils, monocytes, and dentritic cell
APOPTOSIS is the final stage in the life of blood cells.
Thank you Dr, for this informative lecture
I learnt that Haemopoiesis is the process by which blood cells are formed. And they are different site of Haemopoiesis which are
FETUS: 0-2months (Yolk sac) 2-7months (Liver, Spleen) 5-9months (Bone marrow)
INFANTS: Bone marrow (All bones)
ADULTS: Vertebrae, Ribs, Skull, Sacrum
I also learnt about the haemopioetic sites and haemopioetic growth factors
The functions of the growth factors include:
A)Bacterial phagocytosis
B)Prevention of apoptosis in heamopoietic stem cells
C)Enhancement of tumoreghal activities of
macrophages
D)Induction of cell viability and multiplication
And lastly,I learnt the stages of hemopioetic cell development which starts with the Haemapoietic stem cells, Stem cell are capable of self renewal, they give rise
to lineage selection, differentiated into myeloid and lymphoid lineage which are involved in T and B lymphocyte, and Natural killer cells goes to maturation and carry out their functions and undergo apoptosis.
Thank you Dr. For this interesting lecture.
I learnt that, Haemopoiesis is the process of blood cell formation, occurring primarily in the bone marrow, liver, spleen, and embryonic sac during development. It proceeds through stages from pluripotent stem cells to committed progenitor cells, leading to the production of mature blood cells.
Hormone-like growth factors regulate haemopoiesis, acting on stromal cells, pluripotent stem cells, and committed progenitor cells to ensure normal proliferation and differentiation.
Thank you ma for this lecture.
I learnt that Haemopoiesis is the process by which blood cells are formed and it's also called Haematopoiesis. Formed elements of the blood include;
• RBCs - Erythrocytes
• WBCs - Leukocytes
• Platelets - Thrombocytes
Haemopoietic sites include the adult haemopoietic system originates in the embryonic yolk sac and Blood cell production migrates sequentially to the liver,spleen & bone marrow as the embryo develops.
Summary of this sites are;
● Foetus- 0 to 2months(yolk sac)
- 2 to 7months(Liver,spleen)
- 5 to 9months(Bone marrow)
● Infants - Bone morrow(all bones)
● Adults - Vertebrae, ribs,skull,sacrum & pelvis,proximal ends of femur & humerus, sternum and ileum.
Haemopoietic growth factors are naturally occurring hormone like glycoproteins(cytokines) and blood HGF levels rise during infection or following chemotherapy / irradiation.
Functions of Growth factor are regulation of normal haematopoiesis in the bone marrow,stimulation of phagocytosis of bacteria, induction of all viability & cell multiplication,etc.
Stages in haemopoietic cell development is Stem cell - Pluripotent stem cells - Divides to either myeloid progenitor or lymphoid progenitor.
Human stem cells and most haemopoietic rogenitor cells are CD34 positive & CD38 negative.
Haemopoietic stem cells are multipotent and can differentiate to all types of stem cell.
Cell migration from bone marrow to the general circulation is tightly by a complex interplay of signals from the bone marrow micro environment, circulating growth factors and cytokines and feedback mechanisms that accounts for balance production of different blood cells. Blood cells pass from the bone marrow into the blood capillaries through the processes of Homing & Diapedesis.
Homing is a process by which haemopoietic cells move to specific tissues and organs in the body.
Diapedisis is the ability of cells squeezing through the poles of the capillary membrane.
Thank you very much for the lecture Dr. Ify..
I learnt that hemopoiesis is simply the process by which blood cells are formed.
Hemopoietic sure includes;
1. Embryonic yolk sac
2. Liver
3. Spleen
4. Bone marrow
Also blood cell formation before birth includes;
1. Mesoblastic stage: This occurs in the yolk sac and mesothelial layer of the placenta. This takes place from 0-2 months.
2. Hepatic stage: In this stage, the liver and the spleen is the site of blood production. This occurs from 2-7 months
3. Myeloid stage: The main source of production is the bone marrow. It is from 5th- 9th month.
The function of growth factors includes:
1. Regulation of normal hemopoiesis to bone marrow.
2. Prevention of apoptosis of haemopoietic progenitor cells
3. Induction of cell viability and cel multiplication..
Thanks you ma for a wonderful lecture..
Thanks Dr, for this eye opening teaching, indeed it’s worth recommending. I understood that
Hemopoiesis is the process by which blood cells are formed (formation of blood) and can be called haematopoiesis. This further goes down to elements of blood which are
1. Red cells (Erythroblasts)
2. White cells (Leukocytes)
3. Platelets (thrombocytes)
The process by which the above blood cells are formed is called Hematopoiesis
HEMATOPOIETIC SITES
(A) Megaloblastic stage: blood cell formation occurs in the yolk sac and mesothelial layers of the placenta, this occurred for about two months of gestation
(B) Hepatic stage: blood cell formation occurs in the liver and the spleen
(C) Myeloid stage: This is simply the stage where the bone marrow is involved in the blood cell formation and production ( from third months up, the bone marrow becomes the principal site of RBCs and other cells
N/B: > The bone marrow is the sole site of effective hematopoiesis in adult
>when a child is below 5years, all the sites and bone in the system are involved in the blood cell production
>By 18years, hematopoietic marrow is only found in vertebrae, ribs, skull, pelvis, and proximal epiphyses of the femora and humeri
HEMOPOIETIC GROWTH HORMONES (HGF): are naturally occurring hormones, they are required for initiation and sustainance of normal proliferation and differentiation of haemopoietic progenitor cells and formation of mature blood cells
Functions of the growth hormone
1. Regulation of normal haematopoiesis in the bone marrow
2. induction of cell viability and cell multiplication
3. prevention of apoptosis of haematopoietic progenitor cells
4. stimulation of phagocytosis of bacteria
5. enhancement of tumoridal activity of the macrophages
I really enjoyed this lecture Dr
Thank you for the lecture Ma.
I learnt that Haemopoiesis, the process of blood cell formation, occurs in several sites throughout development. Initially, in the mesoblastic stage, it takes place in the yolk sac and placenta's mesothelial layers. This is followed by the hepatic stage, where the liver and spleen become involved in blood cell production. Ultimately, from the myeloid stage onwards, the bone marrow becomes the primary source of red blood cells (RBCs) and other blood cells. At birth, the bone marrow becomes the exclusive site for hematopoiesis in adults.
Haemopoietic growth factors (HGFs) are natural glycoprotein hormones that regulate normal haemopoiesis, promote cell viability and multiplication, prevent apoptosis of haemopoietic progenitor cells, stimulate phagocytosis of bacteria, and enhance macrophage tumoridal activities.
Haemopoietic cell development involves various stages, starting from stem cells giving rise to lineage-committed cells, including myeloid and lymphoid lineages. The myeloid lineage produces RBCs, platelets, and various types of white blood cells, while the lymphoid lineage generates B-lymphocytes, T-lymphocytes, and NK cells, which undergo maturation before exhibiting their functions and undergoing apoptosis.
Blood cells move from the bone marrow into the bloodstream through the processes of homing and diapedesis. Homing involves chemotaxis, adhesion, extravasation, and migration of haemopoietic cells to specific tissues or organs. Diapedesis refers to the ability of cells to squeeze through capillary membrane pores.
Thanks ma’am, this is an interesting lecture. I learnt the following lessons;
Haemopoiesis, also known as hematopoiesis, is the process by which the body produces new blood cells. It occurs primarily in the bone marrow, where stem cells differentiate into various types of blood cells, including red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). This process is crucial for maintaining the body's blood cell levels and overall health.
HAEMOPOIETIC GROWTH FACTORS
IL-1, TNF acts in stromal cells
Stem cell factor, fit ligand: acts on pluripotential stem cells
IL-3, GM-CSF, IL-6, G-CSF, thrombopoietin: acts on multipotential progenitor cells
G-CSF, M-CSF, IL-5, Erythpoietin: acts on committee progenitor cells.
FUNCTIONS OF THE GROWTH FACTORS
Regulation of normal haemopoiesis in the bone marrow.
Stimulation of phagocytosis of bacteria.
Induction of cell viability and cell multiplication
ORGANIZATION OF HAEM
Haemapoietic stem cells
Pluripotent stem cells
Myeloid and lymphoid progenitor cells
RBCs, Megakaryocytes, basophils CFU, Eosinophils
CFU, Granulocytes and monocytes CFU, B-cells, T-cells, and NK cells
Neutrophils, monocytes and dentritic cell
Thankyou for the lecture. Here is the summary of my haematopoiesis:
Hematopoiesis in infants primarily occurs in the liver and spleen, while in adults, it mainly takes place in the bone marrow of the long bones such as the femur and pelvis. Blood formation starts during fetal development and shifts to different locations as the body matures. The liver is involved in blood formation during early development, but the bone marrow becomes the primary site for adult blood cell production.
Thank you Ma for this insightful lecture.
From the video I understood that haemopoiesis is the process by which blood cells are formed.
At embryonic stage, the process is done on the yolk sac which the origin of adult blood system.
Subsequently it migrates to the liver then the spleen and finally the bone marrow.
Generally blood cells uncommitted progenitors are pluripotent stems cell.
Haemopoiesis has
1. Mesoblastic Stage - up 2 months
2. Myeloid stage -:From the 3 month onwards when the bone becmes chiefly involved
3. Hepatic stage - up 7 months where the liver and spleen are involved
Haemopoiesis growth factors are naturally occurring proteins like cytokines which are required for proper dissociation and maturity of progenitor, proliferation, maturity and normal functions blood cells.
Some of their functions include;
1. Regulate normal haemopoiesis in bone marrow
2. Prevent apoptosis of progenitor call
3. Responsible for blood cells viability
Stem cells are capable of self renewal and pluripotent in nature, can differentiate to Lineage selection and can undergo programmed cell death
Thank you ma, in summary, haemopoiesis also known as haematopoiesis is defined as the process by which blood cell are formed. The formed cells are: leukocytes, erythrocytes, thrombocytes. Adult haemopoietic system originates in embryonic yolk sac, blood cell production migrates sequentially to the liver, spleen and bone marrow as the embryo grows. Blood cell formation before birth and after birth was taught, summary of sites of haematopoiesis, haematopoietic growth factors, organization of haematopoietic system, haematopoietic ontogeny, cellular releaseans cellular migrations such as homi ng, adhesion, extravasation, diapedesis. The final stage in the life of a blood cell is death and disposal by apoptosis(programmed cell death). The end products of haemopoietic cell development are cells that are highly specialized for their different functions in the body. RBCs for oxygen transport, WBCs for defence, platelets for blood coagulation.
Wow🤩 what a great lecture on Haemopoiesis. In summary, I learnt that Haemopoiesis or Haematopoiesis is simply the process by which blood cells (Erythrocytes, leucocytes and thrombocytes) are formed.
Haemopoietic sites where this happens are:
1. Embryonic yolk sac
2. Liver
3. Spleen
4. Bone marrow.
Blood cell formation before birth:
Mesoblastic stage- 2 months of gestation
Hepatic stage- 7 months of gestation
Myeloid stage- 3 months above.
Haemapoietic growth factors are naturally-occuring hormone-like glycoproteins (cytokines), required for initiation and sustenance of normal proliferation and differentiation haemopoietic progenitor cells and the function of mature blood cells.
Thank you ma'am😊
I learnt that haemopoiesis is the process by which blood cells are formed, this blood cells include erythrocytes, leucocytes and platelets, i also learnt about the stages of hemopoiesis including mesoblastic stage, hepatic stage and myeloid stage, i also learnt about the hemopoietic sites of blood production, the hematopoietic growth factors, the functions of growth factors, the stages of hematopoietic cell development, how cell are released and finally apoptosis which is programmed cell death.
I also learnt that stem cells are capable of self renewal and differentiation when they divide and are responsible for producing all blood cells throughout life.
Thank you ma
Thank you Ma'am for this lecture.
I learnt that Haemopoisesis is the process by which blood cells are created.
I also learnt about the different sites of Haemopoises whiche are...
1) Festus : 0-2 months (Yolk Sac)
2) 2-7 months (Liver, Spleen)
3) 5-9 months (Bone marrow)
4) Infants : Bone marrow (All bones)
5) Adults: Vetebrae, ribs, skull, sacrum, pelvis, proximal ends if femur and humeri, sternum
Haemopoietic growth factors (HGF) are naturally occuring hormone like glycoprotein.
Some of the function of Haemopoietic growth factors includes
i) Regulation of normal lHaemopoietic in the bone marrow.
ii) induction of cell viability and cell multiplicatiomultiplication
iii) prevention of apoptosis of haemopoietic progenitor cells
iv) Stimulation of phagocytosis of bacteria
v) Enhancement of tumoridial activities of macrophages.
In the Organization of haemopoietic system, the haematopoietic system is an hierarchy of cells in which multipotent haemopoietic stem cells give rise to lineage projenitor cells divides into maturing and mature blood cells.
I understood that Homing is a process by which haemopoeitic cells move to specific tissues or organs in the body while Diapedesis (ability of cells squeezing through the pores of the capillary membrane. This involves a series of steps, namely.
•Chemotaxis
•Adhesion
•Extravasation
•Migration
Thank you ma for the lecture.
From the lecture I learnt that Hemopoiesis is the formation of blood cells(Erythrocytes, Leucocytes and thrombocytes). The sites hematopoiesis in different stages of development: In embryonic stage that is before birth,it is the yolk sac and placenta called mesoblastic stage. Hepatic stage occurs at 2 to 7 months at the liver and spleen. Myeloid stage is where the bone marrow takes over hemopoiesis. At birth, all the bones are involved in cell production Upto 5 years. In adolescents and adults, the vertebrae,ribs skull and other sites takes over. Hemopoietic growth factors are cytokines needed for regulation of haemopoiesis in bone marrow,sustaining the proliferation and differentiation of progenitor cells or stem cells into mature blood cells,stimulating bacteria phagocytosis,prevents destruction of hemopoietic progenitor cells. Haemopoietic system is a hierarchy of cells where multipotent haemopoietic stem cells produces committed progenitor cells which divide to generate mature blood cells. CD34 is the best marker of human stem and progenitor cells. Only 50% of the HSC differentiate into committed cells, the other 50% maintain HSC numbers. HSC differentiate into committed cells, these cells mature and enter the system(blood) and die after it has finished it's work. At each stage of blood cell production,there are different haemopoietic growth factors acting on it: IL-1 and tumor necrosis factor(TNF) acts on stromal cells. Stem cell factor and fit ligands acts on pluripotent stem cells. GM-CSF,IL-6,IL-3,G-CSF and thrombopoietin acts on multipotent progenitor cells. IL-3 acts on committed progenitor cells. When cells are matured in bone, they migrate from bones to blood, this process is regulated by releasing factors. Blood cells pass from boner marrow to blood capillaries through processes like Homing and Diapedesis.
Thank you ma for this educative lecture
In summary
I learnt that haemopoiesis is the process by which blood cells are formed.
The stem cells are the most important cells in haemopoietic cell production, they are ultimately responsible for regenerating haemopoiesis following damage to the haemopoietic system by myelotoxic chemotherapy or after stem cell transplantation.
The end products of haemopoietic cell development are cells that are highly specialized for their different functions in the body ...
I also learnt that haemopoietic growth factor are naturally occurring hormone like glycoproteins i.e cytokines that are required for initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells and the functions of nature blood cells..
Its functions are
. Prevention of apoptosis of haemopoietic progenitor cells.
. Helps in stimulation of phagocytosis of bacteria.
. Enhancement of tutorial activity of macrophages.
. Also for regulation of normal haemopoiesis in the bone marrow.
Thank you Ma for the teaching.
I learnt that Haematopoiesis or haemapoiesis is the process by which blood cells are formed.
The site for adult haemopoietic system is the embryonic yolk sac.
As the adult grows, there is migration from the yolk sac to the spleen, liver and bone marrow.
I also learnt the stages in haemopoietic cell development .
The teachings were understood. Thank you very much Ma 🙏
Thanks Doc. for the lecture.
I learnt that stem cells are capable of self renewal and differentiation when they divide and are responsible for producing all blood cells throughout life.
This session is thrilling, all thanks to you ma.
I learnt about Haematopoesis as a process by which blood cells are formed.
Went further to explain elements of blood formed as:
-Red blood cells
-White blood cells
-Plateletes
Haematopoietic sites min adult system originates in the embryonic yolk sac.
I also learnt haematopoietic sites includes;
-Embryonic yolk sac
-Spleen
-Liver
-Bone marrow
I learnt that before birth blood is formed in stages and these stages includes;
1. Mesoblastic stage from yolk sac and mesothelial layers of the placenta. it occurs up to 2 months of gestation.
2. Hepatic stage from Liver and sometimes spleen. (Up to 7 months).
3. Myeloid stage from the third month onwards, the bone marrow gradually becomes the principal source of RBCs and other blood cells.
In normal adult, production bof blood cells daily is;
-2.5 billion red cells
-2.5 billion platelets
-1.0 billion granulocytes per weight of the body.
After birth and adolescence, active red marrow regresses and focuses on the liver, spleen, vertebrae, shoulder, ribs etc.
Below 5 years, all bones are involved in haematopoesis.
We went further to look at Haematopoietic Growth Factor as naturally occurring hormone like glycoproteins(Cytokines).
we saw it functions as;
1. Regulation of normal Haematopoesis in bone marrow.
2. Induction big cell availability and cell multiplication.
3. prevention big Apoptosis of haematopoietic progenitor cells.
4. stimulation of phagocytosis not bacteria.
5. Enhancement of fumoridal activity of macrophages.
We saw the organization of the haematopoietic system and we saw that it is a hierarchy of cells in which haematopoietic stem cells give rise to lineage committed progenitor cells which later divides to generate the matured red blood cells.
Human stem cells is regulated by a series of molecules known as Cytokines which includes;
-Interleukins
-Stimulating factors.
I learnt about Homing and Diapedesis.
I saw Homing as a process by which haematopoietic cells move to specific tissues and organs.
Diapedesis is the ability of cells to squeeze through the gaps between the poles of the capillary membrane.
Lastly, I saw that stem cells are the most important cells in haematopoietic cell production.
Thank you ma for this wonderful lecture.
I got to understand that Haemopoiesis is a process by which blood cells are formed.
Adult haemopoietic system originates in embryonic yolk sac.
Blood cell Formation occurs in three stages before birth;
-Megaloblastic stage
-Hepatic stage
- Myeloid stage.
I also learnt about the Haemopoietic Growth Factors. The HGFs are naturally occurring hormone-like glycoproteins required for the initiation and sustenance of normal proliferation of Haemopoietic progenitor cells.
Functions of the growth factors includes;
-Regulation of normal hematopoiesis in the bone marrow.
-Induction of cell variability and cell multiplication.
-Prevention of apoptosis of Haemopoietic progenitor cells.
Lastly, i learnt about the sites of Haemopoiesis.
In fetus, at 0-2months is found in yolk sac, at 2-7 months it's being found in the liver& spleen and at 5-9 months it is being found in the bone marrow.
In infants, it is being found in the bone marrow while in Adults it is found in vetebrae,ribs,skull,sacrum&pelvis.
Thank you ma for the lecture.
I learnt that hematopoiesis is the process by which the body produces blood cells. This process begins in the bone marrow, where stem cells give rise to red blood cells, white blood cells, and platelets. First, the stem cells differentiate into different types of progenitor cells, such as red blood cell precursors and white blood cell precursors. Next, the progenitor cells mature into fully functioning blood cells, which are then released into the bloodstream to carry out their various functions. The entire process of hematopoiesis is regulated by various factors, including hormones, enzymes.
Thank you ma for this lecture. In summary, hematopoiesis is the formation of blood cells. Adult haemopietic system originates in the embryonic yolk sac.
Blood cell formation before birth includes mesoblatic stage , hepatic stage, myeloid stage .
The marrow is the sole site of effective haemopoiesis in adult.
Haemopietic growth factor are naturally occuring hormone like glycoproteins required for initiation and sustenance for normal proliferation and differentiation of haemopietic progenitor cell and the function of mature blood cells.
Haemopietic system is a hierarchy of cells in which multipotent haemopietic stem cells give rise to lineage committed progenitor cell which divide to generate the maturing and mature blood cells. Stem cells are capable of cell renewal and differentiation when they divide are responsible for providing blood cells throughout life.
Hematopoietic stem cells are multipotent and differentiate to all type of stem cells. Cytokines controls the proliferation, differentiation of different blood cells.
In cellular release, blood cells pass from the bone marrow into the blood capillaries through the process of homing and diapedesis.
Thank you so much Dr. I learnt alot from this class.
In summary, I learnt that haemopoiesis is the process by which Blood cells are formed. This is basically the formation of blood cells.
The formed element of blood cells ; Red cells, white cells and platelets.
The site of haemopoietic are:
1. Mesoblastic stage: This occurs in the yolk sac and mesothelial layer of the placenta. This takes places from zero to 2 months.
2. Hepatic stage: here, the liver and spleen is the site of blood production. This takes place from 2-7months.
3. Myeloid stage: in this stage, the bone marrow is the main source of production. This from 5-9month.
I learnt that the lifespan of blood cells for RBC is 120days, and that of platelets is 7-10days.
I also got to learn about the function of the growth factors.
1. Regulation of nomal haemotoposis to bone marrow.
2. Induction of cell viability and cell multiplication.
3. Prevention of apoptosis of haemopoietic progenitor cells.
Thank you so much, Dr. This is indeed insightful.
Thanks ma for this video on HAEMOPOIESIS. I understood that haemopoiesis is the process by which blood cells are formed and RBC , WBC and platelets are formed elements of blood. I also understood that adult haemopoietic system originates in the embryonic yolk sac. Blood cell formation before birth , we have the 1.Mesoblastic stage 2.Hepatic stage 3.Myeloid stage.The bone marrow is the sole site of effective haematopoiesis in adult human beings. By the age of 18 years haematopoietic marrow is found only in the vertebrae, ribs , skull , pelvis and proximal epiphyses of the femora and humeri. I understood that haemopoietic growth factors are naturally occurring hormone like glycoproteins required for initiation and substance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of mature blood cells. One of the functions of the growth factors includes regulation of hormonal haematopoiesis in the bone marrow. I understood Homing is a process by which haemopoietic cells move to specific tissues or organs in the body while Diapedesis (ability of cells squeezing through the pores of the capillary membrane).
Thank you ma for this educative lecture. At the end of this lecture, I gained an understanding that Haemopoiesis encompasses the formation of blood cells, occurring across various sites within the body. Before birth, this process unfolds through three distinct stages:
Mesoblastic stage: transpiring within the yolk sac and mesothelial layers of the placenta during the initial 0-2 months of gestation.
Hepatic stage: transitioning to the liver and spleen from 2-7 months of gestation.
Myeloid stage: commencing from 5-8 months onwards, where the bone marrow gradually emerges as the primary source for red blood cells (RBCs) and other blood cell types.
Furthermore, I learnt that at birth, the bone marrow assumes the role of exclusive production site, serving as the sole location for effective hematopoiesis in adults.
Next, I learnt on Haemopoietic Growth Factors (HGF), acting as naturally occurring hormone-like glycoproteins. These factors play pivotal roles, including regulation of normal haemopoiesis in the bone marrow, induction of cell viability and multiplication, prevention of apoptosis in haemopoietic progenitor cells, stimulation of bacterial phagocytosis, and enhancement of macrophage tumoridal activities.
Additionally, the lecture delved into the multifaceted stages of haemopoietic cell development, beginning from the stem pool, where cells renew and differentiate into lineage-committed cells-myeloid and lymphoid lineages. The myeloid lineage yields various blood cell types such as red cells, platelets, eosinophils, neutrophils, and basophils, while the lymphoid lineage gives rise to B-lymphocytes, T-lymphocytes, and NK-cells. These cells progress through maturation stages, fulfilling their diverse functions before ultimately undergoing apoptosis. Thank you
Thank you ma for the lecture, hematopoiesis is the process by which the body produces blood cells. This process begins in the bone marrow, where stem cells give rise to red blood cells, white blood cells, and platelets. First, the stem cells differentiate into different types of progenitor cells, such as red blood cell precursors and white blood cell precursors. Next, the progenitor cells mature into fully functioning blood cells, which are then released into the bloodstream to carry out their various functions. The entire process of hematopoiesis is regulated by various factors, including hormones, enzymes.
Thank you ma'am for this interesting lecture. I've learned that:
HAEMOPOIESIS is the process by which blood cells are formed. This process can also be called HAEMATOPOIESIS.
The formed elements of blood include;
1. Red cells(erythrocytes)
2. White cells( leucocytes)
3. Platelets (thrombocytes).
HAEMATOPOIESTIC SITES
Adult's haematopoietic system originates in the embryonic yolk sac.
Blood cells production migrate sequentially at the liver, spleen and bone marrow as the embryo develops.
Blood cell formation before birth has various stages which include
1. Mesoblastic stage- it takes place at the yolk sac and mesothelial layers of the placenta from zero to 2 months.
2. Hepatic stage- at this stage, blood cells are formed in the liver and also the spleen and this could range up to 7 months.
3. Myeloid stage- from the third month Upwards, the bone marrow gradually becomes the principal source of RBCs and other blood cells.
Blood cells production in the last month is exclusively in the bone marrow.
The bone marrow bis the sole site of effective haematopoiesis in adult human beings.
In normal adults, its daily production amounts to about 2.5 billion red cells and platelets with 1.0 billion granulocytes per kilogram of body weight.
Haematopoietically active (red) marrow regresses after birth untill late adolescence after which time it is focused in the lower skull, vertebrae, shoulder and pelvic girdles, ribs and sternum.
HAEMATOPOIESTIC GROWTH FACTOR
These are naturally occurring hormone-like glycoproteins (cytokines) required for the initiation and sustenance of normal proliferation And differentiation of haematopoietic progenitor cells and the function of mature blood cells. They act on stromal cells : IL-1, TNF.
FUNCTIONS OF GROWTH FACTOR
1. Regulation of normal haematopoiesis in bone marrow
2. Induction of vell viability and cell multiplication.
3. Prevention of apoptosis of haematopoietic progenitor cells.
4. Stimulation of phagocytosis of bacteria
5. Enhancement of tumoridal activity of macrophages.
The haematopoietic system is so organized in a system of hierarchy of cells in which multi potent haematopoietic stem cells will give rise to lineage committed progenitor cells which divide to generate the maturing and mature blood cells.
Morphologically, haematopoietic stem cells are undifferentiated and resemble small lymphocytes.
CD34 is the best known marker of human stem and progenitor cells.
Stem cells are capable of self renewal and differentiation. When they divide, they are responsible for producing all blood cells throughout life.
While in steady state, stem cells divide only 50% of the daughter cells or average differentiate. The remaining 50% don't differentiate but maintain stem cell numbers.
CELLULAR RELEASE
Cell migration from bone marrow to general circulation is totally regulated by a complex interplay of signals from the bone marrow micro environment, circulating growth factors and cytokines and feedback mechanism that account for balanced production of different blood cells.
Cellular migration is under the control of a family of small cytokines termed chemokines.
To leave the bone marrow, the reticulocytes depend on a pressure gradient across the membrane to drive it through the pore
Blood cells pass from the bone marrow into the blood capillaries through these processes; HOMING and DIAPEDESIS.
Homing is a process by which haemopoietic cells move to specific tissues or organs in yhe body. Homing process involves a series of steps and they include;
1. Chemotaxis - cells follow gradients of signalling molecules like chemokines.
2. Adhesion - ability of cells to attach to endothelial cells that line the blood vessels
3. Extravasation - the ability of cells to squeeze through the gaps between endothelial cells then migrate.
CELL DEATH(APOPTOSIS)
The final stage in the life of a blood cell is death and disposal by apoptosis.
Apoptotic cell death is a mechanism for disposing of unwanted or excess cells. It occurs widely in biological systems.
It ensures the distribution of cells without releasing any lysosomal or granule content that would cause an inflammatory reaction.
Apoptosis involves a complex series of events that culminate in the activation of the caspase proteases, fragmentation of DNA and phagocytosis of apoptotic bodies by macrophages.
NOTE:
1. Stem cells are the most important cells in haematopoietic cell production
2. They are ultimately responsible for regenerating haemopoiesis following damage to the haematopoietic system by myelotoxic chemotherapy or after stem cell transplantations. This is accomplished by stem cell division, producing new stem cells to maintain the stem cell pool and differentiating cells that are the progenitor cells of each of the blood cells.
3. The end products of haematopoietic cell development are cells that are highly specialized for the different functions in the body.😮
Thank you very much ma. I learnt that hematopoiesis is simply the process of which blood cells are form . It begins right from embryonic life in the yolk sac till adult Life when it is fully the responsibility of membranous bone marrow. It follows;
0-2 month - yolk sac
2-7 month - fetal liver and sleen
5 month- adolescence - all bone marrow
Adult - membranous bones.
On daily basis hematopoiesis is going on ,with the daily production of blood cells per kg of body weight;
2.5 billion of RBC
2.5 billion of platelets
1 billion of granulocytes.
It is important to note that the activeness of the red bone marrow depletes as one grows until late adolescence when it is fully focused on membranous bones eg. Skull, ribs, vertebrae , sternum, femoral. This is because the red bone marrow is replaced with yellow bone marrow which doesn't take part in blood cells production. This process is influenced by several growth factor/ hormones acting on the various stages of the process. They regulate hemopoietic process, prevent abnormal apoptosis of progenitor cels and induce viability of cells for hemopoiesis; some act on stroma cell ( IL-1, TNF) , some on multipotent progenitor cell( IL-3,:GM- CSF, G-CSF,IL-6) some on the committed progenitor cell (G-CSF,M-CSF, Erythropoietin, thrombopoietin etc)
Stages of hemopoiesis:
It begins with the undifferentiated stem cells which give rise to the pluripotent stem cells which then give rise to the myleloid and lymphoid progenitors which proliferate into the blood forming cells and lymphoid forming cells respectively. The blood forming cells give rise to blood cells; RBC, WBCs while the lymphoid forming cells give rise to the T and B lymphocytes and natural killer cells.
These cells produced in the bone marrow now Carry out homing and diapedesis in order to reach the circulation and various points to location and function.
Thank very much for the lecture. I learnt what Hemopoiesis is all about. Which by definition is the process by which blood cells are formed. The sites at which this blood cells are formed are: Mesoblastic stage, It takes place in the yolk sac , from 2months birth before birth. Hepatic stage, which takes place in the liver,spleen. From 7 months. And Myeloid stage, at this stage the bone marrow is gradually becomes the principle source of the RBCs and other blood cells. Then at the last month, bone marrow exclusively. Hemopoietic growth factors are naturally occurring hormone like glycoproteins(cytokines). One of the function is It regulate the normal haematopoiesis in the bone marrow . The stages in haemopoietc cell development are : From the stem cell pool , to the Renewal which can reverse back the stem cell, gets to differentiation were it migrate to the lineage selection and gets to mature and start functioning , until cell death (apoptosis). Thank you ma
thank you ma for this amazing lecture in summary,Hemopoiesis is defined as the process where red blood cells are formed . the formed blood cells are -Leukocytes
-Erythrocytes
-Thrombocytes
blood cell production in infant
0-2months=Yolk sac
2-7months=Liver ,Spleen
5-9months =Bone marrow
in infant =bone marrow
in adult=vertebrae ,ribs ,skull,Femur
cell migration from the bone marrow to the general circulation is tightly by a complex interplay of signals from the bone marrow environment,circulating growth factor and cytokines are feedback mechanism that account for balance productivity of different blood cells .
Haemopoetic growth factors are naturally occurring hormones like glycoproteins.blood HGF level rise during infection.
Functions of growth factor are
-regulation of normal haemopoesis in the bone made
-it is involved in the apoptosis of haemapoetic proginator cells
- Stimulatin of phagocytosis of bacteria .
Thank you, Dr. I learnt that , haemopoiesis is the process by which blood are formed.
And they are different site of haemopoiesis which are;
Festus:0-2 months ( yolk sac)
2-7 months(liver and spleen)
5-9 month (bone marrow)
Infants :bone marrow (all bones)
Adults:vertebrae,ribs,skull,serum and pelvis .
The haemopoiesis follows a hierarchical organization, starting with multipluripotent haemopoiesis stem cells that give rise to committed progenitor cells.
Haemopoiesis stem cell is also on as HAEMOCYTOPLAST CYTOKINES.
Thank you so much Dr.
Moral lessons:
Haematopoiesis (Haemopoiesis): is the process by which blood cells are formed.
Forms of element:
The Red cell--- Erythrocytes
White cells ----- Glucocyte
Platelets ---- thrombocyte
Blood cell formation before Birth:
1. Mesoblastic stage -- 0 to 2 months of Gestation
2. Hepatic stage --- the liver and the spleen forms the blood cells and take charge of blood production for upto 7 months.
3. Myeloid stage: from the third month onwards the bone marrow gradually becomes the principal source of the red blood cells and other blood vessels.
HAEMOPOIETIC GROWTH FACTORS: These are naturally occurring hormone-like glycoproteins(cytokines)
-- required for initiation and sustenance of normal proliferation and differentiation of HAEMOPOIETIC progenitor cell's and the formation of mature blood cells.
Thank you Ma🙏
3
Thank you Doctor for this lecture. It was an amazing insight coming from you ma
This lecture has given me a clear understanding of Haemopoeisis which is the process by which blood cells are formed and it's site of which it originates in the embryonic yolk sac and also learnt about the stages involved in the formation of blood cells. God bless you ma'am
Thank you so much ma I have learnt about the definition of haemopoiesis and definition of haemopioetic growth factors and also explain its function
Thank you so much for this wonderful lecture.
I was able to understand that haemopoiesis is the process of blood cells formation.
I was also able to understand the different haemopoietic sites which are;
- Originally the embryonic yolk sac
- liver
- spleen
- bone marrow
I was able to understand the various stages of haemopoiesis before birth which are;
- Mesoblastic stage which occurs at about two months of gestation in the yolk sac and mesothelial layers of the placenta.
- Hepatic stage which occurs from the second to the seventh month where the liver and the spleen begin to produce blood cells taking over from the yolk sac.
- Myeloid stage where from the third month onwards, the bone marrow begins to produce blood cells with the liver and spleen slowly relinquishing this responsibility to the bone marrow.
Thank you ma
Thank so much Dr.
In summary, I have learned that Hematopoiesis denotes the process of blood cell formation, encompassing the production of red blood cells, white blood cells, and platelets. It occurs at various hematopoietic sites, including the embryonic yolk sac, liver, spleen, and bone marrow. Before birth, hematopoiesis progresses through three stages: Mesoblastic (up to 2 months gestation), Hepatic (up to 7 months), and Myeloid (from 3 months onwards). Specific growth factors play crucial roles at different stages, affecting pluripotent stem cells, multipotent progenitor cells, and committed progenitor cells. The stages of hematopoietic cell development involve stem cell pool maintenance, differentiation, lineage selection, maturation, function, and cell death.
Thank you ma.
I learnt that Haemopoiesis is the process by which blood cells are formed.
STAGES OF BLOOD CELL FORMATION:
Mesoblastic stage: 0-2 months yolk sac.
Hepatic stage: 2-7 months - liver and spleen
Myeloid stage: 5-9 months- bone marrow.
The adult haemopoietic system originates in embryonic yolk sac and the blood cells production has a sequential migration from the liver, spleen and bone marrow as the embryo develops.
Haemopoietic growth factors are cytokines, they are naturally occurring hormone like glycoprotein, they are required for the initiation and sustenance of the proliferation and differentiation of haemopoietic progenitor cells and the function of matured blood cells.
It was a very understanding session.
I was able to know that Heamopoiesis is a process where by blood cells are formed from haemapioetic stem cells and also the stages of blood cell formation which starts from the
Mesoblastic stage- occurs in the yolk sac from 0-2months
Hepatic stage- occurs in the liver and spleen for 2-7 months
Myeloid stage- occurs in the bone marrow for 5-9 months.
Also I learnt about the haemapioetic growth factors which are known as naturally occurring hormones that are required for the initiation of the normal proliferation of the progenitor cells and how it functions in the maturation of blood cells with it's different stages and functions.
I also learnt that they are two means by which blood cells passes from the bone marrow to the capillaries which are the DIAPEDESIS and HORNING.
Thank you Dr I like ur lectures,I understand that Hematopoiesis - the formation of blood cellular components - occurs during embryonic development and throughout adulthood to produce and replenish the blood system. Studying hematopoiesis can help scientists and clinicians to understand better the processes behind blood disorders and cancers.
Thank you for this wonderful lecture ma, in summary I have learnt the definition of haemopoiesis which is the process by which blood cells are formed. I now know the haemopoietic sites as well as blood cell formation before birth which under it there is the mesoblastic,hepatic and myeloid stage. I have also learnt about haemopoietic growth factors(HGF) which are naturally occurring hormone-like glycoproteins(cytokines). In addition I have learnt the organization of the haemopoietic system in which I picked a point that morphologically, haemopoietic stem cells are undifferentiated and resemble small lymphocytes. I also have learnt the stages in haemopoietic cell development and finally I have learnt about cellular release.
Thank you ma'am, for this educative lecture. In summary, I understood that
Hemopoiesis is the process by which blood cells are formed (formation of blood) and can be called haematopoiesis. This further goes down to elements of blood which are
1. Red cells (Erythroblasts)
2. White cells (Leukocytes)
3. Platelets (thrombocytes)
The process by which the above blood cells are formed is called Hematopoiesis
This includes the following stages
- Megaloblastic stage: blood cell formation occurs in the yolk sac and mesothelial layers of the placenta, this occurred for about two months of gestation
- Hepatic stage: blood cell formation occurs in the liver and the spleen
- Myeloid stage: This is simply the stage where the bone marrow is involved in the blood cell formation and production ( from third months up, the bone marrow becomes the principal site of RBCs and other cells
N/B: > The bone marrow is the sole site of effective hematopoiesis in adult
>when a child is below 5years, all the sites and bone in the system are involved in the blood cell production
>By 18years, hematopoietic marrow is only found in vertebrae, ribs, skull, pelvis, and proximal epiphyses of the femora and humeri
> Functions of the growth hormone
- Regulation of normal haematopoiesis in the bone marrow
- induction of cell viability and cell multiplication
- prevention of apoptosis of haematopoietic progenitor cells
- stimulation of phagocytosis of bacteria
- enhancement of tumoridal activity of the macrophages
Thank you ma'am
Best of it all
Thanks ma for this enlightenment series from this I have learnt what hematopoiesis is all about as the process of blood cells formation that's erythrocyte,leukocyte and thrombocytes, also learned the different stages of these cells formation as embryonic stage from 0-2month and it occurs in the yolk sac and at the endothelial layer of the placenta, the hepatic stage which occurs between 2-7months and it happens at the liver and spleen and the myeloid stage 3-9months and the bone marrow become the principal site and condition of extra medulary haemopoiesis on a condition of bone marrow dysfunction and the liver and spleen takes over again
Also learnt the life span of different cells as RBCs 120days, platelets 7-10days and WBCs few hours and also the daily rate as 2.5 billions of RBCs, 2.5 billion platelets and 1.0 billion granulocytes per kg of body weight of the body
Also learn the hemopoietic growth factor as naturally occurring hormone like glycoproteins (cytokines) required for initiations and sustainance of normal proliferations and differentiation of normal proginators cells and functions of mature blood cells like IL-1,TNF, IL-3,Gm-CSF,thromopoietin etc which act on difference site of the stem cells and there functions as they regulate normal homopoiesis in the bone marrow, prevention of apoptosis in normal proginator cells etc
Thanks ma
Thankyou so much ma after the lectures I learnt that haemopoiesis is the process of formation of blood
Thank you ma'am for this wonderful teaching on haemopoiesis.
At the course if listening keenly i learnt that haemopoiesis is the process by which blood cells are formed. That is;
Erythrocytes
Leukocytes
Thrombocytes
And thr haemopoietic sites are embryonic yolk sac, liver, spleen and bone marrow
The haemopoietic growth factor are naturally occurring hormonal proteins necessary for initiation, differentiation of haemopioetic progenitor cells and normal functions of matured blood cells like the IL-1, TNF, IL-3, thrombopoietin etc which act on different stem cells
Thank you Ma
In summary i learnt that
Hemopoiesis is the process by which blood cells are formed.
Adult haemopoiesis system originates in the embryonic yolk sac.
Blood cell formation before birt, we have the
1.Mesoblastic stage
2.Hepatic stage
3.Myeloid stage
Haemopoietic growth factor are naturally occurring hormone like glycoprotein (cytokines). Tyey initiate and sustain normal proliferation and differentiation of hemopoietic progenitor cells.
Examples stem cell factor, Erythropoietic, Theombopoietic and Fit ligand. These growth factors are responsible for the regulation of normal haematopoiesis in the bone marrow, induction of cell viability and cell multiplication, prevention of apotosis of haematopoietic progenitor cells.
Good day ma I appreciate the time and effort you put in to explain the topic Haemopoiesis. I got to understand that Haemopoiesis is the process in which blood cells are being formed.
Blood cell formation before birth involves three (3) which includes; mesoblastic stage, hepatic stage and myeloid stage.
The mesoblastic stage,this begins in the yolk sac, leading to the liver where erythroblasts and myeloblasts develops.
Hepatic stage,in this stage the liver and spleen are the site of blood cells production.
The myeloid stage, the bone marrow is the site of blood cells production, producing red blood cells, various white blood cells types and platelets.
Thank you ma for this lecture
Hematopoiesis is a process whereby blood cells are formed.
Sites of adult hemopoietic system originates from embryonic yolk sac.
Blood cell production migrates sequentially to the liver, spleen and bone marrow as the embryo develops.
Blood cell formation before birth
*Mesoblastic stage: blood cell formation takes place in the embryonic yolk sac and mesothelial layers of the placenta up to 2 month
*Hepatic stage:
Up to 7months
And the production of blood cells takes place in the liver and spleen
*Myeloid stage: from the 3rd month onwards the bone marrow gradually becomes the principal source of the RBC and other blood cells.
The bike marrow Is the sole site of effective hematopoiesis in adult human beings
Thank you ma for this lecture
In summary, I understood that haemopoiesis is the process by which blood cells are formed. Blood cell production migrates seuentially from the liver, spleen and bone marrow as the embryo develops. The bone marrow is the sole site of effective haematopoiesis in adult human beings. In normal adult its daily production amounts to about 2.5 billion red cells, 2.5 billion platelets and 1.0 billion granulocytes per kilogram of body weight. The site for haemopoiesis in fetus is yolk sac(0-2months), liver, spleen (2-7months) and bone marrow (5-9months). For infants is bone marrow (All bones). For adults is vertebrae, ribs, skull, sacrum and pelvis, proximal ends of femur and humen, sternum and illum. Haemopoiesiss Growth Factors (HGF) are naturally occurring hormone like glycoprotein required for initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells. HGF acts on different stages of bone marrow to bring about their functions. The haemopoietic system is a hierarchy of cells in which multipotent haemopoietic stem cells gives rise to lineage committed progenitor cells which divides to generate the maturing and mature blood cells. CD34 is the best known marker of human stem and progenitor cells. Haematopoietic stem cell is also called Haemocytoblast. Stem cells are capable of self renewal and differentiation when they divide and are responsible for producing all blood cells throughout life.
Thanks Dr, for this lecture on haemopoiesis. Take points
Hemopoiesis/ haematopoiesis is the process of blood formation.
Which involves elements of blood which are
1. Erythroblasts
2. Leukocytes
3. Thrombocytes
The process involved in this blood cells formation is called Hematopoiesis
There are three(3) stages of hematopoiesis:
(i) Embryonic(Mesoblastic) Stage
(ii) Hepatic (Foetal) Stage
(iii) Myeloid Stage
I. Megaloblastic stage: this stage occurs in the yolk sac and mesothelial layers of the placenta, which occurred for about two months of gestation
II. Hepatic stage: this blood cell formation stage occurs in the liver and the spleen
III. Myeloid stage: is the stage where the bone marrow is involved in the blood cell formation and production.
Hematopoiesis Sites:
In Fetus; the hematopoietic sites are primarily yolk sac, liver, spleen.
In Infants; Bone marrow of all bones
In Adult; Bone marrow of Rib, skull, pelvis, proximal end of femur and humeri.
*The bone marrow is the sole site of effective hematopoiesis in adult
*when a child is below 5years, all the sites and bone in the system are involved in the blood cell production
*By 18years, hematopoietic marrow is only found in vertebra proximal epiphyses of the femora and humeri
HEMOPOIETIC GROWTH FACTORS (HGF): this are naturally occurring hormones, that are required for initiation, sustainance of normal proliferation and differentiation of haemopoietic progenitor cells and formation of mature blood cells. They are like glycoproteins.
Examples of HGF; IL-1, TNF, Stem cell factor, GM-CSF, erythropoietin, thrombopoietin, etc.
Functions of the growth hormone includes;
1. Regulation of normal haematopoiesis in the bone marrow
2. induction of cell viability and cell multiplication
3. prevention of apoptosis of haematopoietic progenitor cells
4. stimulation of phagocytosis of bacteria
5. enhancement of tumoridal activity of the macrophages.
In the Organization of haepoietic system, the haematopoietic system is an hierarchy of cells in which multipotent hemopoietic stem cells gives rise to lineage committed progenitor cells which divides and differentiate into maturing and mature blood cells.
Renewal and Differentiation are the unique feature or characteristics of stem cells. Also CD34 is the beat known marker of human stem and progenitor cells.
Blood cells pass from the bone marrow into the blood capillaries through the processes called- Homing and Diapedesis
Homing is the process of hematopoietic cells moves to specific tissues or organs in the body.
It involves a series of steps:
i. Chemotaxis
ii. Adhesion
iii. Extravasation
iv. Migration
Diapedesis is the process or ability of hematopoietic cells squeezing through the pores of the capillary membrane.
Thank you so much for this informative lecture Ma.
I learnt that haemopoiesis is the process of blood cell formation and it passes through three stages before birth.
The mesoblastic stage in the yolk sac
The hepatic stage in the liver and spleen and finally the myeloid stage in the bone marrow 😊
Thank you ma.
In summary, I’ve been able to learn that ,Hematopoisesis is the process of blood formation from haematopoietic cells found in the bone marrow. It is a process where various type of cells are produced from haematopoietic stem cells.
Haemopoietic sites where this takes place :
1. Embryonic yolk sac
2. Liver
3. Spleen
4. Bone marrow.
Blood cell formation before birth:
Mesoblastic stage- 2 months of gestation
Hepatic stage- 7 months of gestation
Myeloid stage- 3 months above.
Haematopoietic growth factor -cytokines , they are required for initiation and sustenance of normal proliferation and differentiation of haematopoietic progenitor cells and the of mature blood cells
Functions includes:
1. Regulation of normal haemapoiesis in the bone marrow
2. Induction of cell viability and cell multiplication
3. Prevention of apoptosis
Apoptosis can be defined as program cell death .
Huming is a process by which haematopoietic cells move to specific tissues or organs in the body
Thank you very much ma.
Thank you mma for this lecture
I learnt that the formation of blood cells are haemopoesis or hematopoesis I also learnt that blood cell formation of adults originate from the bone marrow, but at infant stage or before birth, blood cell formation takes place in the embryo (usually from 0-2 months)
It's is termed as the hepatic stage of blood cell formation or production
The stage where the bone marrow is the principal source of the red blood cell formation is the Myeloid stage
Thank you mma
Thank you for this lecture ma.
I'm conclusion, Haemopoiesis begins in the embryonic yolk sac but shifts to the liver, spleen, and bone marrow as the embryo grows. The bone marrow becomes the primary site of blood cell production after the fifth month of gestation, and it continues to be the sole site in adults. The process involves the formation of blood cells from haemopoietic stem cells, which differentiate into mature blood cells through various stages. Hematopoietic growth factors regulate this process by controlling cell growth, differentiation, and survival. The hematopoietic system consists of a hierarchy of cells, with multipotent stem cells giving rise to lineage-committed progenitor cells, which can either be myeloid or lymphoid. Myeloid lineage produces red blood cells and platelets, while lymphoid lineage generates immune cells. Blood cell migration from the bone marrow to the general circulation is tightly regulated, and apoptosis plays a crucial role in maintaining the balance of blood cells by disposing of unwanted or excess cells.
Thank you Dr Ify for this session
Haemopoiesis
Is the process by which blood cells are formed from the haemopoietic system.
STAGES OF BLOOD CELL FORMATION
Mesoblastic stage: 0-2 months-yolk sac and mesothelial layers of the placenta
Hepatic Stage: 2-7 months - liver and spleen
Myeloid Stage: 5-9 months - bone marrow
Bone marrow is the site of effective haemopoiesis in adults with daily production of : 2.5 billion RBCs, 2.5 billion platelets, & 1.0 billion granulocytes per kg of body weight.
LIFESPAN OF BLOOD CELLS
RBCs -120daya
Platelets-7-10days
HAEMOPOIETIC GROWTH FACTORS
IL-1, TNF acts in stromal cells
Stem cell factor, fit ligand: acts on pluripotential stem cells
IL-3, GM-CSF, IL-6, G-CSF, thrombopoietin: acts on multipotential progenitor cells
G-CSF, M-CSF, IL-5, Erythpoietin: acts on committee progenitor cells.
FUNCTIONS OF THE GROWTH FACTORS
Regulation of normal haemopoiesis in the bone marrow.
Stimulation of phagocytosis of bacteria.
Induction of cell viability and cell multiplication
ORGANIZATION OF HAEM
Haemapoietic stem cells
Pluripotent stem cells
Myeloid and lymphoid progenitor cells
RBCs, Megakaryocytes, basophils CFU, Eosinophils CFU, Granulocytes and monocytes CFU, B-cells, T-cells, and NK cells
Neutrophils, monocytes and dentritic cell
APOPTOSIS: Is the final stage in the life of blood cells.
Thanks Ma'am for the lecture.
Haemopoiesis is the process by which blood cells are formed.
Adult haemopoietic system originates in embryonic yolk sac.
Blood cell production migrates sequentially to liver ,spleen and bone marrow as the embryo develops.
There are 3 stages in blood cell formation before birth.
1) Mesoblastic stage: occurs in the yolk sac and mesothelial layers of the placenta. It occurs in about 0-2months of gestation.
2) Hepatic stage: It occurs in the liver and spleen, 2months ,up to 7months.
3) Myeloid stage: Occurs in the bone marrow from the third month upward and last month in the bone marrow exclusively.
In adult , haemopoiesis occurs in the vertebrae,ribs,skull,sacrum and pelvis, proximal ends of femur and humeri,sternum and ileum.
There are several growth factors that stimulates blood cell formation through proliferation and differentiation of haemopoietic progenitor cells and the function of mature blood cells.These includes; IL-1,TNF,stem cell factor,fit ligand,IL-3,GM- CSF,IL-6 ,G- CSF, thrombopoietin.etc
The haemopoietic system is a hierarchy of cells inwhich multipotent haemopoietic stem cells give rise to lineage committed progenitor cells ,which divides to generate the maturing and mature blood cells.
CD34 is the best known marker of human stem and progenitor cells.Stem cells are capable of self renewal and differentiation when they divide and are responsible for producing all blood cells throughout life.
There are various stages in haemopoietic cell development, these include; stem cell pool, differentiation,lineage selection, maturation, function and cell death(apoptosis).
Thank you very much Ma.
In summary haemopoiesis is the process by which blood cells are formed ,it is also know as haematopoiesis.
Example of site of haemopoiesis in fetus include : yolk sac (0-2months), liver, spleen( 2-7months), Bone marrow (5-9months).
Example of site haemopoiesis in infants is “bone marrow”
Example of site of haemopoiesis in adults includes : vertebrae, ribs ,skull, sacrum,pelvis, sternum.
Haematopoiesis involves haemopoietic growth factors (HGF) are naturally occurring hormone like glycoproteins (cytokines) required for initiation and substance of normal proliferation and differentiation of haemopoietic progenitor cells and function of mature blood cells , examples include: TNF, IL, GM-CSF, GM-CSF, Stem cell factor ,IL-5, M-CSF etc.
Blood cells formed from Hematopoiesis pass from the bone marrow into the blood capillaries through two processes known as Homing and Diapedesis.
The final stage in the life of a blood cell is death and disposal by apoptosis.
Thank you ma'am.
In summary, I learnt that haemopoiesis is the process by which blood cells are formed. I also learnt the different haemopoietic sites such as in adult is vertebrae ribs,skull, sacrum &pelvis and proximal ends of femur and humeri, sternum, illum, then in fetus (0-2months) yolk sac, 2-7months is liver, spleen,5-9months is bone marrow also infants is in the bone marrow . I understood that haemopoietic growth factors are naturally occurring hormone like glycoproteins(cytokines) required for initiation, substance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of mature blood cells . Also, I learnt the functions of haemopoietic growth factors which includes regulations of normal haemopoiesis in the bone marrow, induction of cell viability and cell multiplication, prevention of apoptosis of haemopoietic progenitor cells and stimulation of phagocytosis of bacteria etc. The haemopoietic system is a hierarchy of cells in which multipotent haemopoietic stem cells give rise to lineage- committed progenitor cells which divide to form mature blood cells. Also, haemopoietic stem cells are undifferentiated and resemble small lymphocytes, CD34 is the best known marker of human stem and progenitor cells. Stem cells are capable of self renewal and differentiation when they divide and are responsible for producing all blood cells throughout life. I also understood that in division and differentiation,the pluripotent cells mature to multipotent mixed myeloid (CFU-GEMM)& lymphoid progenitor cells, further division & maturation to committed cells(CFU-GME) and then the uncommitted lymphoid stem cells differentiate to B-cells,T- cells and NK cells. Lastly, I learnt that in cellular release, cell migration from bone marrow to the general circulation is tightly regulated by a complex interplay of signal from the bone marrow micro environment circulating growth factors and cytokines.
Thanks once more ma for this amazing lecture.
Dr ify thank you, from this class i was made to understand what haematopiesis.
Haematopiesis is the process by which blood cells are formed.
I also i understand the site for haematopiesis., which is th main site for haematopiesis (the formation of blood cells) is the bone marrow, which is found in the center of most bones. The bone marrow is a spongy tissue that contains stem cells, which are the cells that can develop into different types of blood cells. In adults, the primary site of haematopiesis is the bone marrow of the pelvis, sternum, and vertebrae. The bone marrow produces red blood cells, white blood cells, and platelets. It also produces stem cells. I also understand haemopoietic growth factor and it functions. And we haemopoietic growth factor are naturally occurring hormone like glycoprotein (cytokine) required for initiation and maintenance of normal proliferation and dissociation of haemopoietic progenitor cell and formation of mature blood cells.
Functions include they involve in preventing apoptosis, regulations of normal haematopiesis in the bone marrow etc.
Stages in haemopoietic development include
1. Haemocytoblast - This is the stem cell that can become any type of blood cell. It divides to produce daughter cells that are committed to a specific lineage.
2. Proerythroblast - This is the first committed cell of the red blood cell lineage. It undergoes a process called enucleation, where it loses its nucleus.
3. Reticulocyte - This is a mature red blood cell that has not yet lost all of its organelles.
Thank you ma, I’m summary
Haemopoiesis is the process of the formation of blood cells.
Haematopoietic sites includes embryonic yolk sac, liver, spleen and bone marrow.
Stages of haemopoiesis are mesoblastic and hepatic stages.
Haematopoiesis growth factors are naturally occurring hormones like glycoprotein required for initiations and maintenance of normal proliferation and dissociation of haemopoietic progenitor cells and formation of mature blood cells. Their functions include:-
- Involvement in cell multiplication and viability
- Prevent apoptosis of progenitor cells
- Regulate normal haemopoiesis in bone marrow.
Thank you ma for this lecture, i have learnt that haematopoesis is the process of blood formation and the site of formation in adults is the bone marrow.
Thank you Doctor
I learnt that haemopoeisis is the formation of blood cells which includes erythrocyte, leucocyte and platelet
I also learned that embryonic yolk sac is where adult haemopoeitic system origin ate
Thank you for the lecture, madam. Below, I have shared some important points on the topic of Hematopoiesis.
Hematopoiesis is the process of forming blood cells in the body, which occurs during embryonic development and throughout adulthood. It takes place in organs and tissues such as the bone marrow, liver, and spleen. The three main types of blood cells are red blood cells, white blood cells, and platelets.
During embryonic development, Hematopoiesis produces only red blood cells, which provide developing organs with oxygen. At this stage, the yolk sac controls hematopoiesis until the placenta is fully developed. As the embryo continues to develop, the hematopoietic process moves to the liver, spleen, and bone marrow, and begins to produce other types of blood cells.
In adults, hematopoiesis of red blood cells and platelets occurs primarily in the bone marrow. However, in infants and children, it may also occur in the spleen and liver.
Haemopoietic growth factors play a crucial role in regulating the differentiation and proliferation of particular progenitor cells and the function of mature red blood cells. These growth factors include IL-1, IL-3, stem cell factor, GM-CSF, etc. They help stimulate phagocytosis of bacteria, enhance tumoridal activity of macrophages, and aid in the regulation of normal hematopoiesis in the bone marrow.
Blood cells pass from the bone marrow into the blood capillaries through two processes - Homing and Diapedesis. Homing refers to the process by which hematopoietic cells move to specific tissues or organs in the body, while Diapedesis is the ability of cells to squeeze through the pores of the capillary membrane.
Studying hematopoiesis helps scientists and clinicians to understand the processes behind blood disorders and cancers.
Thank you ma, I learnt that haematopoiesis is the formation of cells found in the blood,and that the Sites for blood cell formation before birth has 3 stages.
The Mesoblastic stage ( occurs at about 0 - 2months of gestation in the yolk sac), Hepatic stage ( occurs from 2 - 7 months in the liver & spleen) & Myeloid stage ( occurs from 5 - 9 months in Bone marrow).
When a child is below 5yrs, all the bones in the system are involved in hematopoiesis.
By the age of 18yrs it is restricted in the vertebrae, ribs, skull, pelvis & proximal epiphyses of the femora & humeri. Thank you
Thank you ma,
I have understood that haemopoiesis is the process by which blood cells are formed. Adult haemopoietic system originates in the embryonic yolk sac. Blood cell formation before birth are mesoblastic stage(up to 2month), hepatic stage(up to 7month), and myeloid stage(third month onwards).
Site of haemopoiesis in infant is bone marrow, in adults is vetebrae, ribs,skull,sacrum, pelvis etc.
Haemopoietic growth factors are naturally occurring hormone required for initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of matured blood cells. Functions of these growth factors include;
- Regulation of normal haematopoiesis in the bone marrow
- Induction of cell viability
- Prevention of apoptosis
- Stimulation of phagocytosis
Haematopoietic system is a hierarchy of cells in which multipotent haemopoietic stem cells give rise to lineage committed progenitor cells which divide to generate the maturing and matured blood cells.
Blood cells pass from the bone marrow into the blood capillaries through homing and Diapedesis.
Thanks ma for the lecture, Haemopoiesis is the process by which blood cells are formed, before birthday the blood cell formation occurs in three stages which are; mesoblastic stage which occurs in the yolk sac and mesothelial layers of the placenta, it takes place about 0-2 months of the gestation. Hepatic stage where the liver and spleen take up from the previous stage, it take place from 2-7months, Myeloid stage from 5-8 months upwards the bone marrow gradually Because the principal source of red blood cells and other blood cells, bone marrow is the only site of effective hematopoiesis in adult,
Hematopoietic growth factors are natural occuring hormones like glycoproteins they functions include indication of cell viability and cell multiplication, prevention of apoptosis of haemopotic progenitor cell, stimulation of phagocytosis of Bacteria, the stages of haemopotic cell development ranges from stem pool where it gives rise to renewal and differentiate into linage committed cells, to Myeloid stage and lymphoid linage
Thank you ma'am
In summary haemopoiesis also known as haematopoiesis is defined as the process by which blood cells are formed.
The formed blood cells are
1. RBCs - Erythrocytes
2. WBCs - Leukocytes
3. Platelets - Thrombocytes
HAEMOPOIETIC SITES
- Adult haemopoietic system originate in embryonic yolk sac. In the embryonic stage blood cells are formed in the yolk sac
- Blood cell production migrates sequentially to the liver spleen and bone marrow as the embryo grows.
1. Mesoblastic stage:(0- 2months) formation of blood cells occurs in the yolk sac and mesothelial layers of the placenta
2. Hepatic stage: 1- upto 7 months the liver form the blood cells
Spleen also form the blood cells
3. Myeloid stage: from third month onward the bone marrow becomes the principal source of the RBCs and other blood cells
4. Last month: bone marrow exclusively
- The bone marrow is the sole site of hematopoiesis in adult human beings
In normal adult the daily production amount is about 2.5 billion RBCs, 2.5 billion platelets, and 1.0 billion granulocytes per kg of body weight
Thanks ma.
I learnt that haemopoiesis is the process by which blood are formed and is also process of blood cell formation, begins in embryonic sacs like the yolk sac and later involves the liver, spleen and bone marrow.
There are different sites of Haemopoiesis which are
Fetus:0-2 months ( Yolk sac)
2-7 months (liver, spleen)
5-9 months (bone marrow)
Infants: Bone marrow (All bones)
Adults: Vertebrae, ribs, skull sacrum, pelvis, proximal ends of femur and humeri, sternum.
Thank you ma for the lecture..I got to understand that:
Haemopoiesis is the process by which blood cells are formed
Also the haempoietic sites:
Adult haemopoietic system originates in the embryonic yolk sac
Blood cell production migrates sequentially to the liver,spleen and bone marrow as the embryo develops.
Also blood cell formation before birth includes mesoblastic stage,hepatic stage and myeloid stage
The bone marrow is the sole site of effective haematopoiesis in adult human beings.
Sites of haemopoiesis
Fetus:0-2 months (yolk sac)
2-7 months (liver, spleen)
5-9 months (bone marrow)
Infants:bone marrow (all bones )
Adults:vertebrae,ribs,skull,sacrum and pelvis ,proximal ends of femur and humeri,sternum,ileum .
Also ,haemopoietic growth factors which are cytokines requires for the initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of mature red blood cells.
Also the HPGs acts on:
1 stromal cells
2 pluripotential progenitor cells
3 act on multi potential progenitor cells
4 act on committed progenitor cells etc .
Functions of HPGs
1 regulation of normal haematopoiesis in the bone marrow
2 induction of cell viability and cell multiplication
3 prevention of apoptosis of haemopoietic progenitor cells
4 stimulation of phagocytosis of bacteria etc .
In summary,the end product of haemopoietic cell development are cells that are highly specialized for their different functions in the body .etc
Thanks ma for this awesome lecture. First I learnt that Hemopoiesis is the formation of blood cells.
Blood cell formation before birth which is ;
1 mesoblastic stage which occur in the yolk sac,
2. The Hepatic stage which occur in the liver , spleen (up to 7month).
3. The myeloid stage which occur in the bone marrow (from th 3rd month).
I learnt that the bone marrow is the sole site of effective haematopoiesis in adult Humm being..
I also learnt site for haematopoiesis.
For infant - bone marrow
For adults - the vetibrate, ribs skull, sternum, illeum & pelvis.
I also learnt that haematopoiestic growth factor act on ;
1. Stromal cells e.g IL-1, TNF.
2. Pluripotential stem cell e.g stem cell factor, ligand.
3. Act on converted progenitor cells e.g G- CSF , M -CFS .
Function of Growth factor.
1 Regulations of normal haematopoiesis.
2. Induction of cell viability and cell multiplication etc.
To round it up the final stage In the life of blood is death and disposal by apoptosis.
Thank you ma
In summary , I learnt that haemopoiesis is the process by which blood cells are formed .
And I also learnt about the sites of haemopoiesis which are ;the yolk sac,liver,spleen, and bone marrow.
I also learnt about the blood cell formation before birth which are ; Mesoblastic stage ,hepatic stage and myeloid stage .
And also I learnt about the haemopoietic Growth factors which are naturally occurring hormone-like glycoproteins
I also learnt about their functions and also the stages of haemopoietic cell development.
Thank you Dr
I learnt that blood passes from the bone marrow into the blood capillaries through the homing and diapedesis processes.
I also learnt the stages in haemopoietic cell divisions
A really insightful lecture ma,
To summarize, I’d start by defining hemopoiesis which is the process by which blood cells are formed. This hemopoiesis occurs in different sites in the body but this depends on the state of development of the individual. This site of blood cell production migrated from the yolk sac and mesothelial layer of the placenta of the fetus at 2 months, to the liver and spleen of said fetus at 7 months. During the last month, it becomes bone marrow exclamation. The bone marrow is the site of effective hematopoiesis in adult humans. The hemapoietically active marrow regresses after birth until late adolescence after which time it is focused on the marrow of lower skull, vertebrae,shoulder and pelvic girdles,sternum and ribs.
Hematopoietic growth factors are naturally occurring hormone like glycoproteins which are required for the sustenance and initiation of normal proliferation and differentiation of haematopoietic progenitor cells and functions of mature blood cells. Examples of these growth factors in IL-1, Tumor necrosis Factor, IL-3, stem cell factor, fit ligand, IL-6, G-CSF,M-CSF,IL-5, etc.
Their functions include
-Stimulation of phagocytosis of bacteria
-Enhancement of tumoridal activity of macrophages
-prevention of hematopoietic progenitor cells
-induction of cell viability and manipulation
-regulation of normal hematopoiesis in bone marrow.
The stages of development for these hematopoietic cells begin from stem cells which have the ability of self renewal and then differentiate in to lineage committed progenitor cells which then mature and carry out their functions. After this, what comes next is cell death. The end product of hematopoietic cell development is to produce cells which are highly specialized for their function in the body.
Thank you so much ma.
I have gotten knowledge from this topic haempoiesis which is the formation of blood cell, where adult is originate from yolk sac. The blood cell migrate in the liver and the spleen and bone marrow.
Stages of blood cell formation before birth which includes;
1.mesoblastic stage:yolk sac
2.hepatic stage:blood cell is form in the live and spleen
3:myeloid stage:bone borrow
Blood cell formation after birth ;
I.the bone marrow is form in 5years.
II.by age of 18 years which is found in vertebrae, ribs ,skull etc.
Growth factor of haemopoietic which can be called cytokines and it is natural which involves in proliferation and differentiation and also involve function of mature blood cells.
Organisation of haemopoietic systems: which is hierarchy of cells in which multipoint haemopoietic system which give rise to lineage committed progenitor cell.
Cellular release: this involves homing and diapedesis
Lastly you talk about cell death is called apoptosis which is removal of unwanted cell and this processes that occurs doesn't release lysosomal or granule come contents that could cause an inflammatory reaction
Thank you Ma, for this comprehensive lecture. At the end of this lecture I learnt that; Haemopoiesis is the process in which blood cells are formed. Site of Haemopoiesis in adult is embryonic yolk sac. Blood cell formation before birth are of 3 stages;
1. Mesoblastic stage: this occurs in the yolk sac and mesothelial layers of the placenta. It occurs about 0-2 month of gestation.
2. Hepatic stage: The liver and spleen takes up from the preceding stage. This occurs 2-7 months
3. Myeloid stage: in this stage, the bone marrow gradually becomes the principal site of RBCs and other blood cells. This occurs from 7 months upwards.
I also learnt that Haematopoietic growth factor are naturally occurring hormone-like glycoprotein(cytokines). They initiate and sustain normal proliferation and differentiation of hemopoietic progenitor cells. Examples Stem cell factor, Fit Ligand, Erythropoietin, thrombopoietin. These growth factors are responsible for the regulation of normal Haematopoiesis in the bone marrow, induction of cell viability and cell multiplication, prevention of apotosis of haematopoietic progenitor cells, Stimulation of phagocytosis of bacteria, enhancement of tumoridal activity of macrophages.
Thank you ma for this lecture
In summary,
The process by which blood cells are formed is called haematopoiesis
Adult haemapoietic system oroginates in the embryonic yolk sac, blood cell production migrates sequentially through the liver, spleen and bone marrow as the embryo develps
Blood cells development before birth includes;
Mesoblastic stage
Hepatic stage
Myeloid stage
Blood cells synthesis in the final month is entirely in the bone marrow
Haematopoietic growth factor are naturally occuring hormone like glycoproteins necessary for the beginning snd sustenance of appropriate proliferation
Growth factor is important in the regulation of normal haematopoiesis in bone marrow among others
Thank you MA, for this wonderful lecture. I learnt the following at the end of the lecture:
A. HAEMOPOIESIS: It is also called haematopoiesis. It's the process by which blood cells are formed(red blood cells, white blood cells and platelets).
B. SITES OF HAEMOPOIESIS
*FETUS: 0-2months(yolk sac)
2-7months(liver, spleen)
5-9months(Bone marrow)
*INFANTS: Bone marrow (all bones)
*ADULTS: Vetebrae, ribs, sternum, illeum, sacrum and pelvis, proximal end of femur and humeri.
C. HAEMOPOIETIC GROWTH FACTORS:
They are naturally occurring hormone-like glycoproteins(cytokines) required for initiation and sustenance of normal proliferation and differentiation of haemopoietic progenitor cells and the function of mature blood cells.
D. FUNCTIONS OF HAEMOPOIETIC GROWTH FACTORS
1. Regulation of normal haemopoiesis in the bone marrow.
2. Induction of cell viability and cell multiplication.
3. Prevention of apoptosis of haemopoietic progenitor cells
4. Stimulation of phagpcytosis of bacteria
5. Enhancement of tumoridal activity of macrophages.
E. STEPS IN HAEMOPOIETIC CWLL DEVELOPMENT
Haemopoietic cell development starts from the stem cell pool which is capable of cell renewal and leads to differentiation and to lineage selection (myeloid lineage or lymphoid lineage) they undergo maturation, and perform their functions in the body(red blood cells which carries oxygen, white cells for immunity and platelet for coagulation) the encounter cell death(apoptosis), and last stage is removal from the body.
God bless u Dr. What l learnt is that in the process of haematopoietic ontogeny, I describes the development of various blood cells from pluripotent stem cells, and uncommitted lymphoid stem cells (SCs) differentiate into B, T and NK cells. This differentiation process is a crucial aspect of hematopoietic ontogeny, where lymphoid progenitor cells give rise to these specific types of immune cells.
Thank you ma for this information
HAEMOPOIESIS
Tank u ma'am for the worderful lecture, i actually learned about haemopoiesis which is simple mean the process in which blood cell are formed.
There are three elements of blood which are
Red blood cells, White blood cells, Platelets . The process in which this element of blood are formed is called Haemopoiesis.
Site of Haemopoiesis are
Adult haemopoiesis originates in embryonic yolk sac. Adult blood are produced in the bone marrow. The is special migration bfrom the yolk sac to the liver, spleen and bone marrow bas the embryo develop .
Blood cell formation before birth.
Mesoblastic stage this made of yolk sac and mesothelial layer of the placenta .
From two months nof gestation the liver and the spleen take up the work of blood formation.
Hepatic stages. This is up to 7months .
From 5months we have the bone marrow for the production of blood cell
Myeloid stage.this is a stage in which the bone marrow is involved in the production of blood cell.
The bone marrow is the site of haemopoiesis in adult but when the bone marrow compromise it result to extra medullary
Thank you Ma for this interesting Lecture
I learnt that Haemopoiesis is the process of blood cell formation and it progresses through three stages before birth, the mesoblastic stage in the yolk sac, followed by the hepatic stage in the liver and spleen, and finally the myeloid stage in the bone marrow. At birth, the bone marrow becomes the primary site for hematopoiesis in adults. Haemopoietic growth factors (HGF) regulate this process, promoting cell viability, multiplication, and preventing apoptosis. Blood cells develop from stem cells into myeloid and lymphoid lineages, yielding various cell types. They pass from the bone marrow into the bloodstream via homing and diapedesis, involving chemotaxis, adhesion, extravasation, and migration.
Thank you for this great lecture. In summary, have learnt that, HAEMOPOIESIS Is the process of formation of blood cell. There is a
balance maintained between cell renewal, terminal differentiation, cell death and migration.
THREE STAGES OF BLOOD CELL FORMATION before birth;
1.Mesoblastic stage: (0-2 months-yolk sac) and mesothelial layers of the placenta.
2.Hepatic Stage: 2-7 months - liver& spleen.)
3. Myeloid Stage: 5-9 months(bone marrow which is the principal source of RBCS.
There are different sites of hematopoiesis. stem cells are capable of self renewal. Stem cell gives rise to linage selection ,differentiated into myeloid and lymphoid linage which are involved inT,B lymphocyte, and NK cells.goes to maturation and carry out their functions and undergo apoptosis ( programs cell death).
Well explained and descriptive lecture
Thank you Ma for this great insight to Hemopoiesis