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.

Verified step by step guidance

1. Identify the key term 'saltatory conduction' and understand its definition in the context of nerve impulse transmission.
2. Recall that saltatory conduction occurs in myelinated axons, where the myelin sheath insulates the axon and speeds up the transmission of action potentials.
3. Understand that in saltatory conduction, action potentials 'jump' from one node of Ranvier to the next, rather than traveling along every part of the axon membrane.
4. Recognize that nodes of Ranvier are gaps in the myelin sheath where ion channels are concentrated, allowing for the regeneration of action potentials.
5. Evaluate the given options and determine which one correctly describes the process of action potentials being generated only at the nodes of Ranvier.

Key Concepts

Saltatory Conduction

Saltatory conduction is a process by which action potentials jump from one node of Ranvier to another along myelinated axons. This mechanism allows for faster transmission of electrical signals in neurons compared to continuous conduction, where action potentials must propagate along the entire length of the axon. The myelin sheath insulates the axon, preventing ion leakage and facilitating rapid signal propagation.

Nodes of Ranvier

Nodes of Ranvier are small gaps in the myelin sheath of axons where the axolemma is exposed. These nodes are crucial for saltatory conduction, as they contain a high density of voltage-gated sodium channels that allow for the rapid depolarization necessary to generate action potentials. The presence of these nodes enables the action potential to 'leap' from one node to the next, significantly increasing the speed of neural transmission.

Action Potential Generation

An action potential is a rapid, temporary change in the electrical membrane potential of a neuron, triggered when the membrane depolarizes to a certain threshold. In the context of saltatory conduction, action potentials are generated only at the nodes of Ranvier, rather than along the entire axon. This selective generation of action potentials at the nodes is what allows for the efficient and rapid transmission of signals in myelinated neurons.