Action potential

Action potential is a term in physiology that refers to the change in electric potential that is found in nearly all animal, plant an fungi cell membranes. This occurrence is associated with the passage of an impulse along the membrane of a muscle cell or nerve cell. In neurons, they play a central role in cell-to-cell communication. Action potential is opposed to resting potential of a cell. It is the change in electrical potential rapidly rises and falls, following a consistent trajectory. It occurs in several types of animal cells, called excitable cells, which include neurons, muscle cells, and endocrine cells, as well as in some plant cells.

A typical voltage across an animal cell membrane is –65 mV—approximately one-fifteenth of a volt. Because the cell membrane is very thin, voltages of this magnitude give rise to very strong electric forces across the cell membrane.