An action potential is a rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane with a characteristic pattern. ... Depolarization is caused by a rapid rise in membrane potential opening of sodium channels in the cellular membrane, resulting in a large influx of sodium ions.

Does action potential come before depolarization?

When the membrane potential of the axon hillock of a neuron reaches threshold, a rapid change in membrane potential occurs in the form of an action potential. This moving change in membrane potential has three phases. First is depolarization, followed by repolarization and a short period of hyperpolarization.

Why dont the terms depolarization and action potential mean the same thing?

1. Depolarization is the reversal of membrane potential due to an influx of sodium ions, making the neruons more (+) than resting membrane may only be short lived, because depolarization may only reach a level of sub-threshold. but an action potential will only occur if that depolarization hit the threshold.