Question

Action potential conduction velocity is fastest in which of the following fibers?

1) A fibers
2) fibers
3) fibers
4) the conduction velocity is the same for all three fibers

Answer 1

The conduction velocity of an action potential is fastest in A fibers, which are large, myelinated nerve fibers with a larger diameter. The myelination enables saltatory conduction, and the larger diameter reduces resistance, allowing for faster conduction.

Step-by-step explanation:

The conduction velocity of an action potential is fastest in A fibers. A fibers are large, myelinated nerve fibers that have a larger diameter compared to B and C fibers. The large diameter allows for faster conduction of the action potential due to less resistance, similar to how water flows faster in a wider river compared to a narrow creek. Additionally, the myelination of A fibers helps to speed up conduction by enabling saltatory conduction, where the action potential jumps from one node of Ranvier to the next.