Action potential (2)

Action potential 2

The slight depolarisation of the membrane to the point of the threshold causes the voltage dependent sodium channel to open rapidly. This is the initiation of the action potential. The sodium ions rush inside the cell. This results in a depolarisation of the membrane potential towards +10mV, as there are relatively more positive ions inside the cell than there are outside the cell.

1

If the resting membrane potential is -70mV and the threshold is -55mV, a membrane potential of -60mV will: 

2

Action potentials are restricted to areas of excitable membranes that contain voltage-dependent channels.