BONE STRUCTURE
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- Опубликовано: 5 сен 2024
- Besides providing structure and support for the body, and allowing for mobility, bones also protect various organs, produce blood cells, and store minerals. These functions are possible thanks to the tissues that make up the bones. There are two types of bone tissue - cortical bone and cancellous bone. Bones also feature other tissue types, including periosteum, endosteum, bone marrow, cartilage, blood vessels, and nerves.
Cortical bone, also called compact bone, makes up the hard outer layer of bones. It gives bones their smooth and white appearance and makes up 80% of the total bone mass of the skeleton. An osteon, also called a Haversian system, is the primary anatomical and functional unit of cortical bone. It is a microscopic column that tends to run parallel to a bone’s long axis. Osteons have an osteonic or Haversian canal running through their center, surrounded by concentric rings of matrix called lamellae. Haversian canals allow nerve fibers and blood vessels to pass through and supply the bone. Between the lamellae, you have bone cells called osteocytes in small, oblong spaces called lacunae. I’ll describe osteocytes further later in the video. Canaliculi are tiny passageways that radiate from the Haversian canal to the lacunae. Transverse vessels called Volkmann canals run perpendicular to the osteons and connect adjacent osteons. They also connect blood vessels within osteons to the periosteum.
Osteons are densely packed, and spaces between adjacent osteons are filled with interstitial lamellae, which are layers of bone that are generally remnants of previous osteons. Why are there previous osteons? Well, this is due to bone remodeling, or bone metabolism, which is a process in which mature bone tissue is removed through resorption and new bone tissue is added through ossification. Bones are constantly remodelled, because this helps repair microdamages and allows bones to adjust their structure to meet changing mechanical needs. This remodelling is done by specialized cells. Osteoblasts secrete new bone, while osteoclasts break bone down. In addition, there are cells called osteocytes, which result when osteoblasts get trapped in the mineral matrix of bone they’ve created and develop specific features. The space each osteocyte occupies is called a lacuna. Osteocytes can send signals influencing the activity of osteoblasts and osteoclasts and have many other functions. Cortical bone is covered by periosteum on its outer surface, and endosteum on its inner surface. The endosteum forms the boundary between cortical bone and cancellous bone.
Cancellous bone, also called trabecular or spongy bone, consists of a porous network. It’s weaker and less dense but more flexible than cortical bone. Cancellous bone accounts for 20% of total bone mass but has nearly 10x the surface area of compact bone. Cancellous bone is highly vascular and often contains red bone marrow where hematopoiesis, the production of blood cells, occurs. It also has a higher surface area to volume ratio compared to cortical bone, which means it’s better for metabolic activities such as the exchange of calcium ions. Anyway, let’s discuss the structure of cancellous bone.
Cancellous bone is made up of a network of trabeculae, which are its primary anatomical and functional units. Openings on the trabeculae are called canaliculi and these connect to adjacent cavities, instead of to a haversian canal, for blood supply. Within cancellous bone spaces we find bone marrow and hematopoietic stem cells, which are stem cells that give rise to other blood cells, including platelets, red blood cells and white blood cells.
Bone marrow is a nutrient-dense, spongy tissue located in the cavities of bones. It can be found in almost any bone with cancellous tissue and produces both red and white blood cells, as well as platelets. Bone marrow also contains stem cells. In newborns, all such bones are filled exclusively with red marrow or hematopoietic marrow. Red bone marrow produces blood cells. As children age, red bone marrow decreases in quantity and yellow bone marrow increases in quantity. By the age of 25, red bone marrow achieves the final adult distribution. In adults, red marrow is mostly found in the bone marrow of the femur, ribs, and pelvic bones. Yellow bone marrow is located in the hollow cavity of long bones. It is typically found at the center surrounded by red bone marrow. Yellow marrow stores fat and can be called on in life-threatening situations to produce more red blood cells, specifically if you experience rapid blood loss. During these kinds of situations, yellow bone marrow can transform into red bone marrow, producing more blood cells to keep you alive.
3D MODEL: Full Male And Female Anatomy Set Rigged 3D model by 3dMediSphere
Ohhh, you don’t even know how my whole day, yesterday was wasted, all because I couldn’t find a single, concise bone structure video! Everything i watched yesterday was just not sufficient even though the videos were long. Either they included unnecessary details or skipped over certain parts - a complete waste! Instead of those videos,THIS should’ve been the top search result! THANK YOU for making this and THANK GOD, I found it!!!
I never comment on educational videos but this is the most concise helpful video ive ever seen
Thank you so much!! 😊😊😊
Lies again? Net Flix New Foodcourt
I agree, clear and consice yet thorough
काश हिन्दी भाषा में भी कोई इतना अच्छा चैनल होता तो सीखने का मज़ा ही अलग होता 👌👌🤘🤘🤘
Sahi hai yaar!!
One of the topics which is pretty hard to understand without the visuals!! thanks
Always creative and excellent
So well explained!
Awesome
Thank you🙏🏼
Starting orthopedics part final today, that’s why I’m here😁😁
Very creative 😊😊
Nice vedio 😊
Amazing explanation....
Amazing video for better understanding!!
Ohhh I want this video !!! Thanks ❤️❤️❤️
The inward bubble in toilet situation in the morning was suppoosed to come from the connex bone superhero from previous video and it got put on a pregnant belly button situation which failed so then got deployed in the coffee situation
All this earthquake situations are from last weeks solar flares which the core of the earth has absorbed and ready to deploy 😭
Great information😂!
Very well explained thank you
Great video
Please Keep up with this content ❤️❤️
It satisfied my visual learning requirements 🙂
tysmmm! yall explain it so nicely
Wow, jus Wow ❤❤❤❤
Thanks for showing his to me thank you😊
nicely explained
Thank you🎉
Thank you sooooooo much 🫡
can u explain abt gastroenterology
Very helpful,,, thank you very much
Really interesting ❤
more pls
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BONES ARE SOOO FRICKINNN COOOLLLLLL
First fir 🌲
Pretty good!;
Where do I get such pictures , please ?
I drew them
@@NeuralAcademy Wow ، so nice
thank you I will take a screenshots
Appreciable
❤❤
Thnjz
Thanks but bones don't have nerves!
hahaha bro you are wrong
So how we feel pain when our bones injured.
But i can see them
Oh god bones have a lot of nerves man... theyre very painful to break or bruise... you might be thinking of the brain which has no nerves. You can see if you ever buy bones from a butcher for your dog or to make broth there are small holes in the boned where blood vessels and nerves enter through the exterior hard bone if you boil them you will be able to pull out a little white thread which is the nerve and sometimes you get a little grey thread as well which is the blood vessel ...there are not many nerves in the very hard bone on the outside but inside has many and when you get the flu and your bone marrow is going crazy to produce all the immune cells to deal with your flu you can feel your bones hurt a lot from the inside. It's probably the only time most people will feel pain in their bones and its a very painful feeling. But sometimes if you break a bone it hardly hurts at all unless you put pressure on it because the outside hard bone doesn't have a lot of nerves so breaking a bone can feel less painful than say a sprain or something. But I'd say you're mixing bones up with brain. The brain has no nerve endings. The nerve endings branch out and away from the brain so none end in the brain itself. 🧠
Each haversian canal contains an artery,a vein ,a lymph vessels , a nerve and some bone cells
pain