Action potential

Definition

An action potential is a rapid, temporary change in a cell's membrane potential that allows neurons to communicate. It involves the movement of ions across the cell membrane and is essential for transmitting signals in the nervous system.

5 Must Know Facts For Your Next Test

1. Action potentials are initiated when a neuron receives a sufficient stimulus to reach its threshold.
2. The depolarization phase of an action potential is primarily due to the influx of sodium (Na+) ions.
3. Repolarization occurs as potassium (K+) ions exit the neuron, restoring the negative membrane potential.
4. Myelination increases the speed of action potential conduction along axons through saltatory conduction.
5. Adequate nutrition, particularly involving electrolytes like sodium and potassium, is crucial for maintaining proper action potential function.

Review Questions

• What triggers the initiation of an action potential in a neuron?
• Which ion's influx is primarily responsible for the depolarization phase of an action potential?
• How does myelination affect the conduction speed of action potentials?

Related terms

Neuron: A specialized cell that transmits nerve impulses in the nervous system.

Depolarization: The reduction in membrane potential difference across a neuron's plasma membrane, typically due to Na+ influx.

Repolarization: The process by which a neuron returns to its resting membrane potential, usually following depolarization.