Depolarization

Definition

Depolarization is the process by which a neuron's membrane potential becomes less negative, moving towards zero. This change is critical for the initiation and propagation of action potentials in neurons.

5 Must Know Facts For Your Next Test

1. Depolarization occurs when sodium ions (Na+) rush into the neuron through voltage-gated sodium channels.
2. It is a crucial step in the generation of an action potential, which allows neurons to transmit electrical signals.
3. The threshold potential must be reached during depolarization for an action potential to be triggered.
4. Depolarization typically changes the membrane potential from -70mV to around +30mV.
5. After depolarization, repolarization restores the resting membrane potential through the efflux of potassium ions (K+).

Review Questions

• What ion movement causes depolarization in a neuron?
• Why is reaching the threshold potential important during depolarization?
• How does depolarization relate to action potentials?

Related terms

Action Potential:

A rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane.

Repolarization: The process by which the neuron’s membrane returns to its resting potential after depolarization.

Resting Membrane Potential: The voltage difference across a cell membrane when the cell is at rest, typically around -70mV for neurons.