BILD 26 Lecture Notes - Lecture 2: Resting Potential, Electrochemical Gradient, Price Center
Document Summary
Describe the na+ and k+ channels at each numbered point in the diagram to the right: o point 1: resting state both na+ and k+ channels are closed. o point 2: depolarization na+ channel is opened, and na+ can freely flow into cell; k+ channel is still closed. o point 3: repolarization na+ channel is inactivated (open but blocked); k+ channel is opened, and the efflux of k+ is what causes the membrane potential to become more negative. o point 4: refractory period na+ channel is still inactivated, where na+ cannot enter cell (and hence, no action potential can be generated); k+ channel still opened, and additional k+ continue to flow out of cell (which is why the membrane potential goes through that dip). o point 5: return to resting potential ( 70mv) inactivation of na+ channel is removed and all channels close.
