I have Encephalomyelitis, i had destroyed myelin in my brain and in my spinal cord too i got sick last year on 13 February 2013 and i couldn't walk for 2 months after that. Also i had and still having troubles urinating, that's all keeping me away from my social life. I think i saw this video an year ago, but i forgot about it, THANK YOU SO MUCH for this video, now i can play it over and over again to visualize my axons healthy!!! :)
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@@PetarAngelov91 YAAAAY😁😁😁.is it normal to recover from that tho? I wonder if the mental stuff actually worked even if the positive attitude was all that helped. So glad to hear you are all good now stranger.
Na+ is not really transported along the axon via diffusion, it is transported into the axon via diffusion, big difference. Please understand the following: diffusion is a very slow force and is only responsible for the generation of an action potential, not the conduction of the action potential or current itself. Inside the axon the impulse is actually conducted by electrostatic repulsion of positively charged ions that are concentrated very closely to the cellular membrane, K+ mostly. It works like domino, a Na+ (that enters the voltage gated Na+-channel) "hits" a K+ that "hits" another K+ and so on, all the way along the axon. The difference between myelinated axons and unmyelinated axons, is that unmyelinated axons are poorly isolated. The current leaks out from the axon and dies out unless its constantly replenished by new action potential generated by diffusion of Na+ into the axon via voltage gated Na+-channels. It's that easy.
But aren't new action potentials always generated, so they are replenished? Generating new action potentials would speed up the net movement of ions, wouldn't it? Internodal spaces, on the other hand, cannot have the ion channels, so it is impossible to generate new action potentials. Doesn't this imply that Myelin sheaths would decrease speed, not increase?
my professor in my human anatomy and phisiology class is a grumpy old man! he is a former officer in the army and let me tell you it shows the way he teaches his class!!
It isn't the diffusion of Na+ ions down the axon that is fast, it's the electrical charge from each of these ions that is conducted between the nodes of Ranvier that travels very quickly. In unmyelinated axons, the slower propagation of the signal is due to the increased number of ion channels (per unit of distance) that must open and close to maintain the action potential.
@pirateXhunterXzoro The myelin sheath does not allow ions to exit/enter the axon. In a non myelinated axon, depolarization occurs at every step and the speed of the action potential down the axon is slow. In a myelinated axon, the only depolarization occurs at the nodes of ranvier and then the action potential is free to move down the axon until the next node of ranvier.
You're basically correct until the very end. The refractory period only comes into play when the sodium ions diffuse in the opposite direction. If you notice in the video, when the sodium ions pour in, they move both left and right but the message is sent to the right. The reason the potential doesn't occur to the left is because of the refractory period. For a good explanation of the rest, look at Danelawz explanation.
thanks for this animation, it furthers consolidate the info illustrate in the textbook. And I have a question, why there's node of Ranvier? I mean as long as the myelin sheath can speed up the signal transmitting, then why shouldn't the Schwann cells develop a longer length and cover the whole axon, so that the signal can transfer from the hillock straight to the end of axon?
@verosun12 Theoretically yes but there would need to be a Schwann Cell large enough to cover the length of the axon. The Nodes of Ranvier are actually the junction between two Schwann Cells (myelin).
@pirateXhunterXzoro Think of it like a train. The unmyelinated axon has 20 stations on its route and at every station it must stop and unload/load passengers. This slows down the total time the train is moving towards its destination. The myelinated axon is a train with fewer stops. It only has to stop at a smaller number of stations (nodes of ranvier). This allows the the train to get to its destination faster.
I think myelinated axons help nerve signals move faster because there are less channels to open up. The internodes help move the Na+ ions move down the axon faster. When they get to the next node of ranvier, the proper gates open up to trigger another action potential. In an unmyelinated axon, there are more channels that need to open up in order to move the signal along. It is slower b/c I believe you have to wait for the refractory period of each channel to be done.
I want to point out that the open Na+ ion channels do not depolarize the neuron to -60. -60 is the voltage of the inside of the neuron at rest. Also, depolarization means to make less negative. Threshold is reached when the neuron's cytoplasm is depolarized to -55 to -50. The full depolarization of the neuron when the action potential reaches its peak is +50.
Is there a way through an enzyme, vitamin, food etc to activate the Schwann cells to start rebuilding the myelin sheaths that have been destroyed by an autoimmune disease? Thanks for an answer :)
I understand the train example above, but can someone explain in further detail? Like does the action potential start and end (resting) at each node and start again in the myelinated axon or does the influx of sodium in the axon keep the action potential from reaching resting state thus causing it to continually travel until it reaches the synapse? Or am I completely wrong?
I don't think the Na diffuse in, its more like rush in by flux due to the electrical potential created from the K channels. Diffusion is much to slow to cause a signal to be passes quickly.
Can someone tell me why exactly it increases speed? Why does the action potential jump to the nodes of Ranvier? I know the Oligodendrocytes/Schwaan Cells act as a insulator, but that's about it...why doesn't the insulating material stop the electrical conductance? Is it maybe the sodium rushes to where channels are concentrated in the nodes of ranvier? =(???
So the Na gates open, Na floods in because of the voltage difference. Then it becomes +30 inside. If it's +30, why doesn't it rush out again? & if it is more positive on the inside after the Na gate opens, does this push the other positive ions onward, then the K gates open and positive ions flood outward, then that pushes positive Na onward, then that opens the next Na gate and it floods into the cell further down? If so why doesn't it just go in circles between 2 gates?
Amazing,better than a dozen textbooks combined.
-clear and concise.
I have Encephalomyelitis, i had destroyed myelin in my brain and in my spinal cord too i got sick last year on 13 February 2013 and i couldn't walk for 2 months after that. Also i had and still having troubles urinating, that's all keeping me away from my social life. I think i saw this video an year ago, but i forgot about it, THANK YOU SO MUCH for this video, now i can play it over and over again to visualize my axons healthy!!! :)
There are many components to treating neuropathy naturally. One plan I discovered that succeeds in merging these is the Nats Neuro Site (check it out on google) it's the best plan that I have ever heard of. Check out the incredible information .
How's it coming along? I hear nothing but good stuff about powerful symbolic visualization.
@@thispresentmoment7797 It's all good now, im completely healed, but it took me some years to recover ;) Never give up, never back down!
@@PetarAngelov91 YAAAAY😁😁😁.is it normal to recover from that tho? I wonder if the mental stuff actually worked even if the positive attitude was all that helped. So glad to hear you are all good now stranger.
@@thispresentmoment7797 thank you, mate, wish you all the best too, be abundant, be loved, be healthy and be wealthy 🤑🤗🧡
This video gives me a clearer idea on the action potential across a myelinated neuron. Thanks. It helps me in my studies.
simply amazing how the saltatory propagation is illustrated.
Na+ is not really transported along the axon via diffusion, it is transported into the axon via diffusion, big difference.
Please understand the following: diffusion is a very slow force and is only responsible for the generation of an action potential, not the conduction of the action potential or current itself.
Inside the axon the impulse is actually conducted by electrostatic repulsion of positively charged ions that are concentrated very closely to the cellular membrane, K+ mostly. It works like domino, a Na+ (that enters the voltage gated Na+-channel) "hits" a K+ that "hits" another K+ and so on, all the way along the axon.
The difference between myelinated axons and unmyelinated axons, is that unmyelinated axons are poorly isolated. The current leaks out from the axon and dies out unless its constantly replenished by new action potential generated by diffusion of Na+ into the axon via voltage gated Na+-channels. It's that easy.
But aren't new action potentials always generated, so they are replenished? Generating new action potentials would speed up the net movement of ions, wouldn't it? Internodal spaces, on the other hand, cannot have the ion channels, so it is impossible to generate new action potentials. Doesn't this imply that Myelin sheaths would decrease speed, not increase?
Couldn't have said it better myself
WOOOOOOOOOOOOOW!!. it took my book one whole chapter to explain this simple little process.
Nice video. I like the animations that illustrate the most important concepts and are not too flashy.
The best video I've seen so far!Even better than my biology teacher!!
my professor in my human anatomy and phisiology class is a grumpy old man! he is a former officer in the army and let me tell you it shows the way he teaches his class!!
It isn't the diffusion of Na+ ions down the axon that is fast, it's the electrical charge from each of these ions that is conducted between the nodes of Ranvier that travels very quickly. In unmyelinated axons, the slower propagation of the signal is due to the increased number of ion channels (per unit of distance) that must open and close to maintain the action potential.
@pirateXhunterXzoro The myelin sheath does not allow ions to exit/enter the axon. In a non myelinated axon, depolarization occurs at every step and the speed of the action potential down the axon is slow. In a myelinated axon, the only depolarization occurs at the nodes of ranvier and then the action potential is free to move down the axon until the next node of ranvier.
Please make more of these! Very helpful!
Watching this was more fun than playing videogames! I hope that my axons stay myelinated forever!
You're basically correct until the very end. The refractory period only comes into play when the sodium ions diffuse in the opposite direction. If you notice in the video, when the sodium ions pour in, they move both left and right but the message is sent to the right. The reason the potential doesn't occur to the left is because of the refractory period. For a good explanation of the rest, look at Danelawz explanation.
thanks for this animation, it furthers consolidate the info illustrate in the textbook.
And I have a question, why there's node of Ranvier? I mean as long as the myelin sheath can speed up the signal transmitting, then why shouldn't the Schwann cells develop a longer length and cover the whole axon, so that the signal can transfer from the hillock straight to the end of axon?
best neuron video so far on youtube
@verosun12 Theoretically yes but there would need to be a Schwann Cell large enough to cover the length of the axon. The Nodes of Ranvier are actually the junction between two Schwann Cells (myelin).
@pirateXhunterXzoro Think of it like a train. The unmyelinated axon has 20 stations on its route and at every station it must stop and unload/load passengers. This slows down the total time the train is moving towards its destination.
The myelinated axon is a train with fewer stops. It only has to stop at a smaller number of stations (nodes of ranvier). This allows the the train to get to its destination faster.
Very good video! (:
Congratulations for the animation and the script, you made me understand finally what is the treshold. (:
I think myelinated axons help nerve signals move faster because there are less channels to open up. The internodes help move the Na+ ions move down the axon faster. When they get to the next node of ranvier, the proper gates open up to trigger another action potential. In an unmyelinated axon, there are more channels that need to open up in order to move the signal along. It is slower b/c I believe you have to wait for the refractory period of each channel to be done.
this is great for students of ALL levels
Really cool!!!... this is really awesome and looks so professional.
I want to point out that the open Na+ ion channels do not depolarize the neuron to -60. -60 is the voltage of the inside of the neuron at rest. Also, depolarization means to make less negative. Threshold is reached when the neuron's cytoplasm is depolarized to -55 to -50. The full depolarization of the neuron when the action potential reaches its peak is +50.
Amazing
Is there a way through an enzyme, vitamin, food etc to activate the Schwann cells to start rebuilding the myelin sheaths that have been destroyed by an autoimmune disease?
Thanks for an answer :)
Thank you for this video! It is very clear, and helped me a lot in my understanding of saltatory conduction!
I understand the train example above, but can someone explain in further detail? Like does the action potential start and end (resting) at each node and start again in the myelinated axon or does the influx of sodium in the axon keep the action potential from reaching resting state thus causing it to continually travel until it reaches the synapse? Or am I completely wrong?
I don't think the Na diffuse in, its more like rush in by flux due to the electrical potential created from the K channels. Diffusion is much to slow to cause a signal to be passes quickly.
Superb presentation 😍
Helped alot
Nice job there! Oh and a great day to everyone reading this! :)
Elegant , simple and enjoyable
Very helpful, thank you. Great music too, really enjoyed it. :)
Thanks for explaining....the Action potential
Excellent overview. Thanks!
Can someone tell me why exactly it increases speed? Why does the action potential jump to the nodes of Ranvier? I know the Oligodendrocytes/Schwaan Cells act as a insulator, but that's about it...why doesn't the insulating material stop the electrical conductance? Is it maybe the sodium rushes to where channels are concentrated in the nodes of ranvier? =(???
Awesome summary. Excellent work
Great visualisation and explanation, Thank you!
@PuraVid4 if the whole axon was covered in myelin would it travel faster since theres no stops?
Great information
@plmqas Actually I believe she said that myelin was *thickest* in adolescence, which is why teenagers have such quick responses.
thank you so much this video is so good for ranvier node..
I'm so confused at 3:55 - 4:20. Can someone explain in simple terms why myelinated axons are faster than unmyelinated?
What does she mean by the inside of the cell reaching -60? Is that the charge or temperature?
why myelin sheath does not covered the entire neuron ?
Why there is gap Between Two myelin sheath ?
So the Na gates open, Na floods in because of the voltage difference. Then it becomes +30 inside. If it's +30, why doesn't it rush out again? & if it is more positive on the inside after the Na gate opens, does this push the other positive ions onward, then the K gates open and positive ions flood outward, then that pushes positive Na onward, then that opens the next Na gate and it floods into the cell further down? If so why doesn't it just go in circles between 2 gates?
Makes so much sense now!! Thanks.
I heard of something about changing electric potentials... does that have something to do with myelin?
the rushing in and out of Na+ and K+ is not quite clear here.
Can someone please tell me the name of the song playing? or who it's written by?
Thank you💙💙
this is really amazing!! i like the light background music as well :)
awesome video
@chrissline77 Thanks I'm glad a post I made a while ago was able to help someone out :)
Best video out there! Thanks a milion! :)
"axoplasm" is incorrectly captioned as "ectoplasm."
Wonderful video! Thank you!
Because node of ranvier is the only place where the ion channels are
great video!
awesome video got alot of things to learn
Those Sodium symbols pouring out remind me of scrolling combat text.
Very Helpful....i know ima ace my Physiology quiz tomorrow
2:15 Does anyone know what the stimulus is?
What software was used to make this animation?
cheers for that much better than my bio teacher!!
Is the myelin sheath made up of Schwann cells or oligodendrocytes? Or both? How so?
I'm confoozed!
Oligodendrocytes are the glial cells present in the CNS, whereas Schwann cells are present in the PNS.
Great Video , Thanks much
You have to love it
Great and very helpful job thanks alot.
Awesome video I agree with Reminiscable this is better than be distracted by some video games : D!!!
This is great.Thanks
Very Helpful.Thank you!
wow , it was very useful , thanks a lot . everything was s good , voice and animation .
best explanation of the neuron of i've ever seen in my life. Narration skillz need a little bit of work though
That's how I understand it. It is probably wrong and I would love to have someone correct me.
Its a grade saver for me thank you so much.
good info thanks
*انا طالب في الشهادة الثانوية العامة*
(بكالوريا)
في syria
وأريد أن أعرف كيف يتشكل غمد النخاعين؟
ولم أجد الشرح المناسب!
@@Haidar.13
انت سوووري؟
thanks for uploading on youtube =D helped A LOT!! lol i wish my lectures are conducted on youtube.
Thanks!
Helped a lot! Thank you
Thank you!
awesome
thank you
VERY usefull. it helped me alot, thanx.
Thanks
very helpful
good one
Amazing one....Thanks a lot:)
Thank you. Helped a lot:)
I love uuu thank u for alll your videos
thanks a bucketlaod lady!
I thought the narrator was "Myelin Shopper"
Thank you :)
go CAVALIERS. VIVA Johnson County Community College :* I'll miss you even though I love KU.
You probably already understand this. I thought it fascinating
this was helpful
thank's :D great animation
Ha! Nothing so lofty. I actually made the score by looping some tracks in Garage Band. :-)
bst video about action potential
Good vid.