The Action Potential: Ionic Basis and Molecular Mechanisms

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@jonahansen 4 жыл бұрын

These are by far the best explanations on KZbin about ion gradients, membrane potentials, action potentials, and their physical underpinnings. Best graphics, accurate, and well narrated.

@mziem 4 жыл бұрын

I am a neuroscience grad student and this 11 min video answered AT LEAST 5 questions that I have been trying to answer. I can't even imagine how much time and frustration it saved me. From the bottom of my heart, THANK YOU!!!

@PeteMeighan 4 жыл бұрын

I'm glad this video helped! Thank you for passing along the positive comment. Good luck to you in grad school!

@brentporter986 4 жыл бұрын

Pete, just started med school. These are incredible videos. It takes time for KZbin channels to gain traction, but I am confident this will do that in 2-3 years.

@PeteMeighan 4 жыл бұрын

Thank you so much for the kind and encouraging words. I sincerely appreciate it! Best of luck to you in med school!

@piwini 7 ай бұрын

you are great explainer!! thank you for your videos!

@jonahansen 4 жыл бұрын

One aspect of action potentials that is inaccurately described in a number of other clips on KZbin is that they state that the inward flow of sodium during depolarization changes the concentration of sodium inside the axon, and that sodium ions then flow down the axon a distance to activate the next portion, with the sodium-potassium pump subsequently restoring the concentration gradient and thus repolarization. This is misleading; only a minute number of sodium ions need flow through the open channel to reverse the membrane potential, and the voltage change at the adjacent portion of the membrane is due to the electric field/current that is restricted to the inside of the axon and decays due to current leakage. This is why saltatory conduction works when portions of the axon are myelinated to reduce current leakage and speeds up conduction velocity of action potentials in those fibers. Generally, hundreds to thousands of action potentials can occur even without working sodium-potassium pumps until the concentration gradient decays since only a very few ions cross the membrane via the activated channels. This is implied in this video, but is a major point of confusion in most others that really ought to be emphasized. Thanks for the videos; as I commented earlier, they are the best I've seen!

@PeteMeighan 4 жыл бұрын

Wow, thank you very much for the thoughtful review of my videos! I sincerely appreciate it. What you described above has been my issue with a majority of videos discussing the various physiological processes published on KZbin. Frequently, they either: a) fail to bite down on the mechanistic features of the topic in question; or b) just get it wrong. I love physiology and I love thinking about it mechanistically. Thank you again!