The Action Potential: Animation

The following animation 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.