Action Potential/Myelination

[muchokaren]

I have a sort of stupid question. I had this pretty simple question on an exam and it has been bothering me ever since.

True or False: Myelination increases the speed of an action potential.

Now, if the question stated, “Myelination increases the conduction speed of an action potential”, I would have answered “True”. But I answered “False” since it didn’t specify action potential conduction/propagation.

So I guess what I’m asking is, does myelination increases the actual AP? Or the conduction of said AP down the axon?

Thanks

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[Matthew9Thirtyfive]

True or False: Myelination increases the speed of an action potential.

I mean, this is true. Myelination and increasing axon diameter are two ways to increase AP velocity. Myelination does it primarily by decreasing capacitance. Without getting too detailed, the AP is transmitted from node to node by electric charge as opposed to passive ion spread. So by increasing the conduction of the AP down the axon, you are increasing the speed of the AP.

Incidentally, the strength of the AP in the myelinated region is actually decreased. By that doesn’t affect the speed due to the above.

I think you might be overthinking it. Or maybe I’m under thinking it. But when I see a the term AP speed, I immediately assume they mean conduction velocity, since that’s what that is.