This job describes the events that must occur to generate an action potential (AP). It then relates the sequence of changes in permeability to changes in the ion channels and explains why the AP is an all-or-none phenomenon.© BrainMass Inc. brainmass.com October 9, 2019, 7:03 pm ad1c9bdddf
When a graded potential results in a depolarization of the membrane potential to a certain critical point, an AP is triggered. Two types of ion channels are involved in the generation of an AP: sodium channels and potassium channels.
A resting membrane potential is around -70 mV. A slight depolarization will not result in an AP unless the critical potential is reached. This critical potential is called the threshold. Once threshold is reached, sodium channels open wide and sodium ions flow into the cell. This influx of positive charges into the cell diminishes the electrical difference (voltage) across ...
Facts to support that the action potential is an all-or-none phenomenon are contained.