Which of the following is responsible for facilitating rapid conduction of the wave of depolarization along an axon?

Question

A. Unmyelinated areas of the axon.

B. The rate at which the cell membrane returns to RMP

C. The duration of the action potential

D. The entire duration of the action potential

I chose A. Becuase the action potential travels down the axon as the membrane of the axon depolarizes and repolarizes. Nodes of ranvier are gaps in the myelin along the axons; they contain sodium and potassium ion channels; allowing the action potential to travel quickly down the axon by jumpig from one node to the next.

Answer 1

Hi Mike O.,

I'd have to agree with your assessment. "Facilitating" is more nebulous than "causing"; for "causing" one would have to say the myelinated sections, since the current is essentially instantaneously shunted outside of them, hence the element of speed. The function of the nodes of Ranvier is to keep the impulse from dissipating over too-long stretches of myelinated axon, so they are supporting ~~ facilitating.

All other aspects of impulse (onset, duration, reset) do not affect speed much. Well, maybe the first, a little, but even so....

-- Cheers, -- Mr. d.