Action potential (3)
Action potential 3
When the transmembrane potential reaches the highest level of +30mV (complete depolarisation), the sodium channels will close. At the same time, the potassium channels will open (due to the membrane potential of +30mV) and potassium ions will leave the cell down their electrical and chemical gradient. With the opening of the potassium channel the repolarisation is initiated.
Action potentials are restricted to areas of excitable membranes that contain voltage-dependent channels.
Extra info: An action potential cannot be generated in a membrane without voltage dependent channels.