The video should clarify that it is referencing smooth muscle and not skeletal muscle because skeletal muscles do not have gap junctions. The introduction of the "worm" makes it seem like the video is about voluntary muscles, when it is not.
I for one, as a medical student is very grateful for this medical section of Khan. Thank you so much - your making my quest at mastering the basic sciences just a bit easier. Even us students need a refresher every once in awhile.
hi guys. thank you very much. my only request is not to get disappointed by the less number of views in the medicine section. it is just because there are less number of doctors. please keep up the good work. expecting video on ECG from you guys.
7:10 Is'nt this strictly not found in Skeletal Muscle? From what I've read, Skeletal Muscle is one of the few tissues that completely lacks Gap Junctions.
You have a point, its cardiac muscle that require gap junctions for syncytium to keep inherent rhythm I know that one for sure, but I'm on the fence with SK.M having gap junctions if anyone could clarify..
MrLimo217 If Im not completely wrong, the term Syncytium refers to either cells that are a result of fusion of many cells, or cells that works as one with numerous Gap Junctions. In Skeletal Muscle, the first part is true. Instead of Gap Junctions, the cells (Myoblasts) simply fused to form long fibers known as Myocytes (Multinucleated). Although this is a really good video, I believe that it is slightly mistaken in this part. Each Muscle Fiber is a syncytium of previous Myoblasts, and the muscle fibers are all innervated independently from eachother (But usually by the same Nerve - Motor Unit) Gap Junctions is currently considered to be stricly non-existent in Skeletal Muscle.
It's not Gap Junctions, it's the transverse tubule. Myofibril is surrounded by sarcoplasmic reticulum and the T-tubules run between them, feeding into multiple ones, so when one triggers the release of calcium, the ion can either bind to troponin to open the binding site of actin, or can travel down the tubule and open subsequent SRs to bring in even more calcium.
Yeah I was caught off guard as well, so I don't think his example of "kicking a ball" fits for this example per se since skeletal muscles lack gap junctions
You should have noted Tropomyosin and troponin. These inhibit the ability of muscle cells to contract if not "moved out of the way". Not only does the calcium tell neighboring cells to contract, the calcium is also NEEDED to move Tropomyosin and troponin from the muscles. If Tropomyosin and troponin is not removed by calcium, the muscle will continue to be relaxed and you will NOT be able to "do the worm". Great informational video with great notes!!! Thank you!!
As always Khan academy is the 'Best' actually I don't leave reviews after watching a video but here I m with one for Khan academy keep going on with your good work 👍fighting ✊
It would be better if you explained more in details such as End Plate Potential and Muscle action potential and how it works through T - Tubules, DHP, and RyR.
Yup, skeletal muscle cells don't have gap junctions after early development. Motor units (motor neurons + the skeletal muscle fibers they innervate) are responsible for activating groups of skeletal muscle fibers.
Thank you for making this video as I did find it helpful. Not to get nit-picky, but rather to clarify for my own understanding, I thought you were originally talking about skeletal muscle and it was my understanding that only cardiac muscle and visceral smooth muscle that were connected by gap junctions to form a functional syncytium? I thought that each skeletal muscle cell was innervated by a motor neuron.
Great video!! Love it. Question: But what about the Potassium ion exiting the muscle through the postsynaptic membrane as Sodium enters. Is that not that important???
Genuinely amazed at how I can sit in a 1 hour lecture, attempt the homework, be completely lost , but then watch this 9 minute video, and immediately understand everything and make the homework a breeze. Incredible!
Isn't calcium-induced calcium release more relevant in cardiac muscles? I've learned that in skeletal muscle, the influx of calcium will cause a change in the dihydropyridine receptors (DHPR) which will cause them to physically "poke" and activate the ryanodine receptors (RyR) that allow calcium from the SR to enter the cell and bind to troponin C.
Isn't this video more descriptive of how cardiac muscle cells contract via gap junctions, not just muscle in general? I feel like that should be included in video. Great video other than that.
this is teh best video i have seen on this topic and on nearly any topic. Thank you so much. The only thing is DHP receptors (i think) in opening the sacroplastic recticilium! thanks again!
Dihydropyridine receptors are present on the sarcolemma inside the t-tubule which when activated by Ca2+ undergo a conformational change that activate Ryanodine receptors on the sarcoplasmic reticulum to release more Ca2+.
sorry but this video presenter is confusing smooth and skeletal muscles. No differentiation of acetylcholine ion gated channels v sodium voltage gated channels, or acetylcholinesterase, or end plate potential v action potential, or T tubules (which is how the AP spreads deep into the sarcolema. Great video though, just a few corrections are needed. Khanacademy rocks as always tho
I thought the dihydropyradine receptor was physically linked to the ryanodine receptor on the SR in skeletal muscle cells, so it would not be calcium induced.
Can anyone tell me why this question below is false? I can't seem to find the answer. Is it because it is not in the motor end or is it because it doesn't inactivate Acetylcholine but rather activate it? The muscle's electrical response is turned on by an enzyme present in the motor end-plate which inactivates ACh
The end of the axon terminal is called the synaptic knob not exocytosis. Exocytosis is the ACTION of the ACh exiting out into the synaptic cleft. PLEASE USE THE APPROPRIATE TERMINOLOGY. This subject is hard enough without having to jump around to 10 different youtube videos just to find the ONE PERSON who says synaptic knob.
Now how does this work better in Michael Jordan than for me Lol interms of Jumping higher.. Or getting stronger shock absorbers in legs so I don't wear down after landing after jumping during games
Bless you Khan Academy for working towards high-quality free education
+Bernie Sanders ya know someone pays for it
i love you bernie
Well said old man
The video should clarify that it is referencing smooth muscle and not skeletal muscle because skeletal muscles do not have gap junctions. The introduction of the "worm" makes it seem like the video is about voluntary muscles, when it is not.
Good point!
Yeah i was getting confused about the gap junctions and all those calcium channels. I’m glad i checked comments before watching the whole video.
More specifically single unit smooth muscle(hollow visceral,intestine and pre capillary sphincter) and another type of muscle called cardiac muscle
I for one, as a medical student is very grateful for this medical section of Khan. Thank you so much - your making my quest at mastering the basic sciences just a bit easier. Even us students need a refresher every once in awhile.
Understood a 9 minute video more than I did with an hour worth of lecture, that I paid for. Thanks 🤧
I literally just said the same
lol, i'm sitting here answering the questions like university level Dora the explorer
Same here!
hi guys. thank you very much. my only request is not to get disappointed by the less number of views in the medicine section. it is just because there are less number of doctors. please keep up the good work. expecting video on ECG from you guys.
brb, I gotta go high-five my best bro
What about the T-tubule that lies in between the sarcoplasmic reticulum?
I really appreciate all your efforts to teach in high quality videos. They are amazing!
this is the best video i have seen on this topic and on nearly any topic. Thank you so much
Excellent explanation, helped me with my sports physiology exam massively!
This was exceptional. You explain such a complex topic so eloquently thank you.
A great video, yet a 5:25 onward an odd smooth/skeletal muscle hybrid was created.
Thank you so much! You are much better than any text book.
u are all really AWESOME GUYS!!!! A clean and clear manner of telling:) bravo no need any academy buildings.. COS there is KHAN ACADEMY...
7:10
Is'nt this strictly not found in Skeletal Muscle? From what I've read, Skeletal Muscle is one of the few tissues that completely lacks Gap Junctions.
You have a point, its cardiac muscle that require gap junctions for syncytium to keep inherent rhythm I know that one for sure, but I'm on the fence with SK.M having gap junctions if anyone could clarify..
MrLimo217 If Im not completely wrong, the term Syncytium refers to either cells that are a result of fusion of many cells, or cells that works as one with numerous Gap Junctions. In Skeletal Muscle, the first part is true. Instead of Gap Junctions, the cells (Myoblasts) simply fused to form long fibers known as Myocytes (Multinucleated).
Although this is a really good video, I believe that it is slightly mistaken in this part. Each Muscle Fiber is a syncytium of previous Myoblasts, and the muscle fibers are all innervated independently from eachother (But usually by the same Nerve - Motor Unit)
Gap Junctions is currently considered to be stricly non-existent in Skeletal Muscle.
It's not Gap Junctions, it's the transverse tubule. Myofibril is surrounded by sarcoplasmic reticulum and the T-tubules run between them, feeding into multiple ones, so when one triggers the release of calcium, the ion can either bind to troponin to open the binding site of actin, or can travel down the tubule and open subsequent SRs to bring in even more calcium.
+Zaid Mousa Skeletal muscles do not have gap junctions. Only cardiac and smooth muscles do. So IDK what khan is doing in this video.
Yeah I was caught off guard as well, so I don't think his example of "kicking a ball" fits for this example per se since skeletal muscles lack gap junctions
Can you add a note on the video that gap junctions are not found in skeletal muscle cells please!!
whoa! y'all know how to explain stuff so we can actually get it
thanks for the great work
You should have noted Tropomyosin and troponin. These inhibit the ability of muscle cells to contract if not "moved out of the way". Not only does the calcium tell neighboring cells to contract, the calcium is also NEEDED to move Tropomyosin and troponin from the muscles. If Tropomyosin and troponin is not removed by calcium, the muscle will continue to be relaxed and you will NOT be able to "do the worm". Great informational video with great notes!!! Thank you!!
I liked the way how you explained it.
Thanks a lot....
This explains better than my professor did.
As always Khan academy is the 'Best' actually I don't leave reviews after watching a video but here I m with one for Khan academy keep going on with your good work 👍fighting ✊
It would be better if you explained more in details such as End Plate Potential and Muscle action potential and how it works through T - Tubules, DHP, and RyR.
Great video! However, I believe that skeletal muscles lack gap junctions.
Genesse Arriaga guess some
Yup, skeletal muscle cells don't have gap junctions after early development. Motor units (motor neurons + the skeletal muscle fibers they innervate) are responsible for activating groups of skeletal muscle fibers.
Next time I high five my bro I will remember this
Thank you for making this video as I did find it helpful. Not to get nit-picky, but rather to clarify for my own understanding, I thought you were originally talking about skeletal muscle and it was my understanding that only cardiac muscle and visceral smooth muscle that were connected by gap junctions to form a functional syncytium? I thought that each skeletal muscle cell was innervated by a motor neuron.
Amazing video! A tough lesson easily explained!
Incredible!!! thanks so much guys
i love how excited he is talking about this lololol
What about the T-tubule?
Thank you so much. This helped me really understand the neuromuscular junction.
Thank you so much for clarifying neuromuscular junction just under 9mins. It helped me visualise the mechanism better with your clear presentation.
You're the man!
Thank you for more information
Great video!! Love it. Question: But what about the Potassium ion exiting the muscle through the postsynaptic membrane as Sodium enters. Is that not that important???
Really great video here, you are an excellent instructor Dr. Narayan. If you ever get tired of practicing, you will make an excellent Professor.
Genuinely amazed at how I can sit in a 1 hour lecture, attempt the homework, be completely lost , but then watch this 9 minute video, and immediately understand everything and make the homework a breeze. Incredible!
I THANK YOU SO MUCH YOU HAVE HELPED ME A LOT IN MY PARAMEDIC PROGRAM
as always thank you
This just saved me 50 worths of slide. Thank you!
So grateful thank you 💗
Thank you....this was really helpful!
His handwriting is so goooddd
I'm obsessed with your handwriting
Thank you for making this stuff so easy to understand
this is an excellent video, but what about Potassium voltage-gated channels?
Isn't calcium-induced calcium release more relevant in cardiac muscles? I've learned that in skeletal muscle, the influx of calcium will cause a change in the dihydropyridine receptors (DHPR) which will cause them to physically "poke" and activate the ryanodine receptors (RyR) that allow calcium from the SR to enter the cell and bind to troponin C.
Thank you, this is the comment i was looking for! You've just answered the question i had in my mind.
Thank you so much Sir
Isn't this video more descriptive of how cardiac muscle cells contract via gap junctions, not just muscle in general? I feel like that should be included in video. Great video other than that.
I think only cardiovascular muscle cells have gap junctions, so that the heart can contract as a whole (more or less). Not skeletal muscle.
Thank you sir ❤️
this is teh best video i have seen on this topic and on nearly any topic. Thank you so much. The only thing is DHP receptors (i think) in opening the sacroplastic recticilium!
thanks again!
Dihydropyridine receptors are present on the sarcolemma inside the t-tubule which when activated by Ca2+ undergo a conformational change that activate Ryanodine receptors on the sarcoplasmic reticulum to release more Ca2+.
Big help! Thank you!
very well explained.....quick qstn, where do t-tubule's come in??
I am a l class 10 student and this is the best explanation I ever had
Thanks a lot
تحفة يغالي
Really helpful
god bless you 🌼
Perfect explanation. THANK YOU!
Thankyu great work
sorry but this video presenter is confusing smooth and skeletal muscles. No differentiation of acetylcholine ion gated channels v sodium voltage gated channels, or acetylcholinesterase, or end plate potential v action potential, or T tubules (which is how the AP spreads deep into the sarcolema.
Great video though, just a few corrections are needed. Khanacademy rocks as always tho
How is arcolemma is different from typical plasma membrane?
Skeletal muscle does not have any cell cell junction, cardiac muscle has desmosomes and gap junction, smooth muscle has gap junction.
Thumbs up for the best intro ever
What about the theory that says the Ach is released by rupture because of dense bars in the axon terminal ?
you are great
my god !!!amazingggg
How can I cite this as a source in a paper
Skeletal muscle does not have gap junctions.
GREAT JOB! Keep up the good work, thanks for helping me out! :)
Aulia Yusti also please watch applied aspects related to neuromascular transmission on my channel
th-cam.com/video/RvjI_iuFsPw/w-d-xo.html
Better than my professor.
what the hell is motor end plate?
the motor end plate is on the sarcolemma that receives the ach
What happen if we have a lot of Na+ comming in?
I thought the dihydropyradine receptor was physically linked to the ryanodine receptor on the SR in skeletal muscle cells, so it would not be calcium induced.
Roy F Yes.
It is Ca induced in cardiac muscles
Can anyone tell me why this question below is false? I can't seem to find the answer. Is it because it is not in the motor end or is it because it doesn't inactivate Acetylcholine but rather activate it?
The muscle's electrical response is turned on by an enzyme present in the motor end-plate which inactivates ACh
T tubules not mentioned once
What's a motor end plate?
The end of the axon terminal is called the synaptic knob not exocytosis. Exocytosis is the ACTION of the ACh exiting out into the synaptic cleft. PLEASE USE THE APPROPRIATE TERMINOLOGY. This subject is hard enough without having to jump around to 10 different youtube videos just to find the ONE PERSON who says synaptic knob.
the worm?😬
Can you elaborate in hindi plz
Now how does this work better in Michael Jordan than for me Lol interms of Jumping higher.. Or getting stronger shock absorbers in legs so I don't wear down after landing after jumping during games
WOW
أحبك
❤️
that was great
🤩🤩🤩🤩🤩
this guy really likes the worm
lmao at how he says every term two times
Sal you are my demon
what did i do to deserve you people?
n
Very helpful