HLSC 1200U Lecture Notes - Lecture 16: Resting Potential, Myelin, Saltatory Conduction
Document Summary
At rest, all of the sodium ion channels are closed whilst a few potassium channels are open. Voltage gated channels only open when there is a change in electrical activity. The sodium channels are all closed, because it needs to wait until the resting membrane potential is more positive. When there"s a nerve impulse, step one is that the sodium gated channels open and sodium goes into the cell. Potassium then leaves the cell, and the potential difference of the cell goes down. Before a second action potential needs to happen, all the sodium has to be kicked out of the cell, and the potassium must go back inside the cell, in other words, a reset. The sodium potassium pump aids in this reset. Uses atp as an energy source, it returns three sodium ions out of the cell, and kicks back two potassium ions into the cell.
