An action potential is an electrical signal that passes along the membrane of a neuron or muscle fiber. When an applied electrical stimulus is beyond a certain level called the threshold of excitation, a massive depolarization of the membrane occurs.
Any small subthreshold stimulation of the membrane produces a small response which is proportional to the amount of current applied. Any stimulation which is beyond the threshold of excitation produces the same large response, regardless of how far beyond the threshold the stimulus is. This response is called the action potential, during which the electrical membrane potential of a cell rapidly rises and falls.
This page created 06 Sep 2011 00:25
Last updated 21 Jul 2016 23:21