Question

Which of the following statements best describes saltatory conduction?
a. Every section of the axolemma must be depolarized and triggered to generate an action potential.
b. The internodes must generate action potentials.
c. The dendrites and cell bodies propagate EPSPs toward the trigger zone.
d. Only the nodes of Ranvier must generate action potentials.

Accepted Answer

Understand the concept of saltatory conduction: Saltatory conduction is a process in which action potentials 'jump' from one node of Ranvier to the next along a myelinated axon. This occurs because the myelin sheath insulates the axon, preventing ion exchange in the internodal regions and speeding up signal transmission. Review the structure of a myelinated axon: Myelinated axons have regions covered by myelin (internodes) and small gaps between these regions called nodes of Ranvier. The nodes of Ranvier are the only places where ion exchange (depolarization) occurs during an action potential. Analyze the role of the nodes of Ranvier: During saltatory conduction, action potentials are generated only at the nodes of Ranvier. The myelin sheath prevents depolarization in the internodes, so the signal 'jumps' from node to node, making conduction faster and more efficient. Evaluate each answer choice: a) Incorrect, because not every section of the axolemma is depolarized in saltatory conduction; only the nodes of Ranvier are involved. b) Incorrect, because the internodes do not generate action potentials; they are insulated by myelin. c) Incorrect, because this describes the propagation of excitatory postsynaptic potentials (EPSPs) in dendrites and cell bodies, not saltatory conduction. d) Correct, because only the nodes of Ranvier generate action potentials in saltatory conduction. Conclude that the correct answer is the statement that describes the generation of action potentials only at the nodes of Ranvier, which is option d.

비슷한 문제에 대한 검증된 영상 답변:

주요 개념

Saltatory Conduction

Nodes of Ranvier

Action Potential