Question

How is an action potential propagated along an axon?

A. An efflux of potassium from the current action potential depolarizes the adjacent area.
B. An influx of sodium ions from the current action potential depolarizes the adjacent area.
C. Stimuli from the graded (local) potentials from the soma and dendrites depolarize the entire axon.

Answer 1

The propagation of an action potential along an axon is achieved through the opening and closing of voltage-gated ion channels, particularly sodium (Na+) channels. As the axon is depolarized, Na+ ions rush in, allowing the depolarization to spread. This process continues down the length of the axon, enabling the action potential to propagate.

Step-by-step explanation:

The propagation of an action potential along an axon relies on the opening and closing of voltage-gated ion channels. The action potential is initiated at the initial segment of the axon, where a high density of voltage-gated sodium (Na+) channels allows rapid depolarization. As the depolarization spreads down the length of the axon, more voltage-gated Na+ channels open, allowing the influx of Na+ ions and spreading the depolarization farther. This process continues, with the depolarization moving in a wave-like fashion down the axon as more voltage-gated Na+ channels open.