Online College Courses for Credit

Membrane Potential and Action Potential

Membrane Potential and Action Potential

Author: Nathan Lampson

This lesson will describe how the differences in concentrations of ions across a plasma membrane set the stage for a nerve impulse.

See More
Fast, Free College Credit

Developing Effective Teams

Let's Ride
*No strings attached. This college course is 100% free and is worth 1 semester credit.

26 Sophia partners guarantee credit transfer.

308 Institutions have accepted or given pre-approval for credit transfer.

* The American Council on Education's College Credit Recommendation Service (ACE Credit®) has evaluated and recommended college credit for 28 of Sophia’s online courses. Many different colleges and universities consider ACE CREDIT recommendations in determining the applicability to their course and degree programs.

Terms to Know
Action Potential

A nerve impulse.

Input Zone

The region of a neuron where signals enter.

Output Zone

The part of the neuron that consists of the axon endings, where signals are sent on to another neuron or to a gland or muscle cell.

Resting Membrane Potential

The difference in the charge across a cell membrane.  

Resting Potential

The steady voltage difference that occurs across a neuron’s membrane when it is not being stimulated.

Sodium Potassium Pump

A protein embedded in the plasma membrane that actively transports sodium and potassium against their concentration gradients.


The minimum voltage shift across a membrane required for an action potential to take place.

Trigger Zone

The part of the neuron located at the base of the cell body that initiates action potentials.