×

Conduction of action potentials

6716

0

HWC

• Action potentials must be rapidly conducted over long distances in order for the nervous system to communicate with other cells. • Propagation of an action potential uses processes similar to those that generate the potential at the trigger zone. • a When a graded potential reaches threshold and triggers an action potential, a positive feedback cycle begins. • As voltage gated Na+ channels open, and Na+ions flood into the cell, this segment of the membrane depolarizes until its voltage is reversed. • At the peak of the action potential, the influx of sodium cause sodium gates in the adjacent segment of the membrane to open. • At the same time gated K+ channels are opening and Na+ channels are closing, repolarizing the original segment of the membrane and placing it in a refractory period. • During the refractory period a second action potential cannot be generated in this portion of the membrane. • However, the graded potential can depolarize to threshold in the segment in front, thus generating another action potential. • This cycle continues along the length of the axonal membrane from trigger zone to the axon terminals.

Share

Embed

Copy and paste this code into your website or blog.

Add To

You must login to add videos to your playlists.

Comments

0 Comments total

to post comments.

No comments have been posted for this video yet.