Question

How does an action potential travel along a myelinated axon?

A) The action potential jumps from one myelinated area of the axon to the next.
B) The action potential jumps from one nonmyelinated area of the axon to the next.
C) There are no gaps in a myelinated axon: the action potential jumps from the beginning of the axon to the terminal.
D) Myelin helps the nerve impulse cross the synapse from one myelinated nerve to the next.

Answer 1

An action potential travels along a myelinated axon by jumping from node to node across the nonmyelinated gaps, known as nodes of Ranvier, due to saltatory conduction.

Step-by-step explanation:

How an Action Potential Travels Along a Myelinated Axon

An action potential in a myelinated axon travels by a process known as saltatory conduction. This occurs because the myelin sheath acts as an insulating layer, making the axon more resistant to current leak and allowing for faster signal transmission. The myelin sheath is periodically interrupted by unmyelinated gaps known as the nodes of Ranvier. At these nodes, the concentration of voltage-gated Na+ and K+ channels is high, facilitating the rapid regeneration and 'jumping' of the action potential from one node to the next. As a result, the action potential effectively 'jumps' from node to node instead of traveling continuously along the axon, which significantly speeds up neural signal conduction.

In summary, the correct answer to the question is B) The action potential jumps from one nonmyelinated area of the axon to the next, which corresponds to the nodes of Ranvier.