The Action Potential: Animation

The following animaltion should help you to see how the action potential moves along the axon's membrane.  If your browser doesn't support animated graphics or for a look at each individual step of this process, take a look at the action potential images that make up this animation.

Animated graphic: Copyright 1997, Carlos Finlay and Michael R. Markham.

 Notice how the action potential involves an influx of  Na+ which causes a region of positive charge that then opens nearby Na+ channels. This "chain reaction" is how the action potential moves down the axon. Just behind the axtion potential, K+ channels open and K+ ions leave the axon taking a positive charge with them. This brings the axon back to resting potential. 
Please note that this animation was created by Michael R. Markham who is not affiliated with UMass Boston.
Use this link to access the original and updated versions.

Last updated July 21, 2006.  Comments to markham@fiu.edu