4 Action potentials

48 9 6 an ac0on poten0al consists of several changes

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ing s0mulus 0 –50 Threshold Res0ng poten0al Depolariza0ons –100 Ac0on poten0al –100 0 1 2 3 4 5 Time (msec) (b) Graded depolariza0ons 0 1 2 3 4 5 Time (msec) (c) Ac0on poten0al Fig. 48-9 6 An ac0on poten0al consists of several changes across the plasma membrane. The changes include: Changes in the conforma0on of par0cular integral membrane proteins called voltage ­gated ion channels. New transmembrane ionic currents through these ion channels. Change in the transmembrane poten0al (Vm) caused by the ionic currents. Here’s a look at the events in an ac0on poten0al: Fig. 48-10-1 Key Na+ K+ Membrane poten0al (mV) +50 Ac0on poten0al –50 Plasma membrane Cytosol Inac0va0on loop 1 Res0ng state 2 4 Threshold 1 5 1 Res0ng poten0al Depolariza0on Extracellular fluid 3 0 –100 Sodium channel Time Potassium channel NOTICE: Both of these channels are voltage ­gated channels, not the ones that produce Vrest! Undershoot Fig. 48-10-2 Key Na+...
View Full Document

This note was uploaded on 02/18/2012 for the course BILD 2 taught by Professor Schroeder during the Spring '08 term at UCSD.

Ask a homework question - tutors are online