BIOL 3327 Lecture Notes - Lecture 43: Atrioventricular Node, Resting Potential, Pacemaker Current
15 Jul 2020
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Document Summary
Differences between non-pacemaker and pacemaker cell action potentials. These currents in the muscle cells are driven by the na+ ion. Pacemaker cells: represented by sa and av nodes that have slow, continuous depolarization even when they"re at rest. Slow generated currents driven by ca2+, and a repolarization phase driven by k+. There isn"t really a resting current in the pacemaker cells. Pharmacologic effects of channel blockade at pacemaker cells in sa node. Sa node fires on its own because there are spontaneous depolarizations constant changes in the currents (prepotentional). Sometimes you see it called a funny current because it"s basically the effects of several different channels that change the electrical conductance. First, where the prepotential spontaneous depolarization is, there are na+ leak channels, as well as ca2+ leak channels. The ca2+ channels are called t-type channels and they"re only open in very negative voltages, leaking ions into the cell.
