Muscle Contraction - Cross Bridge Cycle, Animation.
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- Опубликовано: 6 сен 2024
- (USMLE topics) Molecular basis of the sliding filament theory (skeletal muscle contraction) - the cross bridge cycle.
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Voice by: Sue Stern
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Muscle contraction is at the basis of all skeletal movements. Skeletal muscles are composed of muscles fibers which in turn are made of repetitive functional units called sarcomeres. Each sarcomere contains many parallel, overlapping thin (actin) and thick (myosin) filaments. The muscle contracts when these filaments slide past each other, resulting in a shortening of the sarcomere and thus the muscle. This is known as the sliding filament theory. Cross-bridge cycling forms the molecular basis for this sliding movement.
- Muscle contraction is initiated when muscle fibers are stimulated by a nerve impulse and calcium ions are released.
- To trigger muscular contraction, the troponin units on the actin myofilaments are bound by calcium ions. The binding displaces tropomyosin along the myofilaments, which in turn (and) exposes the myosin binding sites.
- At this stage, the head of each myosin unit is bound to an ADP and a phosphate molecule remaining from the previous muscular contraction.
- Now, the myosin heads release these phosphates and bind to the actin myofilaments via the newly exposed myosin binding sites.
- In this way, the actin and myosin myofilaments are cross-linked.
- The two myofilaments glide past one another, propelled by a head-first movement of the myosin units powered by the chemical energy stored in their heads. As the units move, they release the ADP molecules bound to their heads.
- The gliding motion is halted when ATP molecules bind to the myosin heads, thus severing the bonds between myosin and actin.
- The ATP molecules bound to myosin are now decomposed into ADP and phosphate, with the energy released by this reaction stored in the myosin heads, ready to be used in the next cycle of movement.
- Having been unbound from actin, the myosin heads resume their starting positions along the actin myofilament, and can now begin a new sequence of actin binding.
- Thus, the presence of further calcium ions will trigger a new contraction cycle
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This is my 2 hour class in less than 3 minutes 🤯🤯
Thats so true
Sad truth
Fucking truth
RIGHT
So true
Its crazy how this all happens in nano seconds
Qocoshu the body has been refined through natural selection over thousands of years. Modern firearms have not.
@@yesimfunatparties9337 Well if body developed all these structures, would the primitive men be paralysed maybe?
so, we can say that there is a god
@@Abdullah-co8zj why should it be god? which god would it even be?
complexity increases when many simple things which are able to work together fuse into one thing. it doesn’t need god
@@manofgod7622
So how all this happen in the first place?
By chance?
By nature?
I don't think so
I spent 9 hours yesterday trying to grasp this concept. Thank you for summing it up in 2 minutes!!!
Lol😂
Find a good teacher..
My teacher taught this in less than a minute!! 🤡
@@harshrai2679 that's good for you! consider yourself blessed.
I know right? I had it backwards the entire time 😂😂😂
Really?
Are u single?
short, succinct, to the point, animated. No unnecessary comments that take up time or throw me off. Thank you so very much for this and so many other videos.
i literally made notes from the narration
your standards sure are low.
Literally one of my favorite teaching videos. I watched it when I took A&P, again in pathophysiology, and again in graduate level pathophysiology lol! Such a simple refresher that talks about the essential steps in muscle contraction. Thank you.
You're making my first semester at med school a bit easier. Best video I've watched on this process so far. Thanks a lot from Germany!
Edit in 2022: since I'm still getting replies to this comment, just fyi, I'm taking my written final exams in April 2023 and I'll be a doctor after a practical year and one more oral exam in April 2024. And I've forgotten all about the cross bridge cycle lmao
Edit in 2024: My final exam is actually in June, I just didn't quite know how it works two years ago lmao
Final edit in June 2024: I'm a doctor!
I'll start my residency in anesthesiology in October 🥳
Thanks for watching!
2 years in, hows it going buddy?
@@postmelon645 wow haha this took me aaall the way back! it's actually 3 years now, i just wrote this at the end of the 1st semester that's probably why it says 2. and it's amazing, I'm loving it! I've seen and done so many amazing things already! I've already forgotten everything about muscle contraction though haha
@@postmelon645 idk why but your comment made very happy
@@airotkiv that's great! I'm in my 3rd year of medical school too now. Lol don't worry, even I forgot all about muscle contractions, that why I watched this video today
I'm so mad this concept was easily explained in 2 minutes as opposed to my class lectures with over 8 hours of content. SO THANK YOU
My teacher was juz amazing then❤❤
This 2 minute video did a better job than what my professor did in a hour
When ADP is there - cross bridge forms. (+)
When ATP is there - cross bridge breaks. (-)
A salute to the person who studied all this and introduced us with this concept.
I'm preparing for my neet exam (Medical entrance exam in india) and your videos helping me a lot to understand those concepts.. how can i tell you that how much you helping me by providing this types of awesome visualised animation.
Same here buddy. Let's crack it!! 💪🏻
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I'm preparing for mdcat medical entrance in Pakistan 😊 best of luck bro
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I'm a neet aspirant too😁, watching this for my weekly exam and this helped a lot.
This 2 and a half minute video just taught me more than my 3 hour lecture.
I am not a medical student or professional. Just a patient in pain going to physical therapy who was just told that 7I likely have Actin Myosin Crossbridge. All the info out there is confusing and difficult to understand. This was the easiest to understand for anyone not in a medical profession! Thank you!
this is seriously one of my most favorite videos on the internet
Ikr- Explained well
@@tanvi2618 hey army hahaha
Thankyou so much that was very helpful
It's crazy that this process takes place in our bodies at any given moment, and that it never fails. Life is bizarre.
Life is multi fucken level complex*
And still people don't believe in The Creator, God Almighty.
I keep thinking about this concept every time I pick up my pencil to write, use my fingers to type or scroll, or just get up to stretch throughout the entire process of studying. It's just like, "Oh, this is what's happening in my body at this exact moment."
Thanks to anatomy, now I know how amazing our bodies are.
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Great description. It's really clarifying to see the molecules interact like this. Thank you
I have a exam for tomorrow and i watch this video that is the best video to lern and understand❤
First semester at med school, lots of gratitude from Greece!
Yesterday I spent 8 hours, and now I just learned in a few minutes, thank you
I was reading this on my textbook, but no matter what I do, I cannot grasp what it was describing even though it has pictures of the process.
Thanks to this video I am now able to gain a little more understanding of what I am studying
This animation is amazing. This helps me connect all that I'm learning together so that it makes sense. Thank you so much for your work in making this animation available for anyone. You are truly the best!
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Ayushi Verma
Ayush verma...........
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My mentor takes 2hrs to complete this topic but after seeing this my illusion level increased .... Thanku soo much🙏☺️✨🔥
2 min is equal = 4 hours class
Thanks for animation ❤️
Best taught by NOMESH GOPALANI SIR 🎉
Hours of concepts in such a small video. Can't thankyou enough ❤️
Spent 2 hours grasping the concept from the text. Finally understood this. Now, I can go through the text and learn.
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Animation makes learning easier
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I am very thankful to this video
me reading the comments: "thankyou for helping us for med school"
le class 11 students in india: a whole topic regarding this in biology textbook
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Aziz al şu patsoları
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Additional info:
Nerve impulse are transferred via the T-tubules from the sarcolemma
It is the Troponin C that the Calcium ion binds to (4 Calcium ions per one Troponin C)
Thank you. This is a concept in our 11th class books. Love from India.
I was studying this topic for more than 4 hours but nothing went in my head.....but after watching this vedio i understood so well thank you foe te awesome explanation ❤️❤️
I'm a neet student exam on 7 may ,I'm revising locomotion n movement then sudden I want to see this in 3d 😊🤘
I can see a definite corkscrew design in the central troponin and tropomyosin. Thus, the archimedean screw action applies. Thus, there is no pulling here. The myosin filament grabs and pushes the filaments and releases.
w teacher fr😍
saved hours of studying
Thanks a lot for the video, it was very comprehensible
3d visualization is verry help ful of better understanding
Our body is amazing, imagine all of this happening a million times per second for the rest of our lives.
WELCOME ARJUNAZZ...❤👀
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Professores de Biologia molecular passaram 2 semanas falando e confundindo minha cabeça, e essa mulher me faz entender em 2min, semdizer 1 só palavra em português
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Unimaginable Really whole Lecture Of More Than 2 Hours iN 2 minutes 😮❤
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Ty so much I was not able to understand the ATP concept , but you cleared my concept
All I needed was this : 2:16
Ca is of much importance in muscle 💪 contractions
ATP is powerful
Myosin ATpase is functional in ATP break down releasing energye
I am a MMC Student...i am understand this concept very much... tq u for this video
Incredible video. What I seemed to not understand became so clear with this video! Thank you
The way of teaching made easy
Tremendous work indeed ! Thou have explained about 1 or 2 paragraphs in just a few minutes and animated the concept as well.
Excellent 3D revision video
This explains my whole life's understanding of excitation contraction coupling. Thank you.
You're very welcome!
How it's possible in nano second 🤯🤯🤯🤯
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i still dont understand anything
Go and study you will
Thats your problem
@@Lovely-bh3lnthis stuff isnt easy. It can be very confusing to students.
Maybe,You're just stupid😂
dumb😊
I don’t know how people are confused about this topic. It’s pretty easy for me to grasp 😅
perfect for a visual learner
Am in high-school rn and this really helped me with my biology class..thanks!
Straight to the point.. making my sem easier..❤
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