AP PSYCHOLOGY

Detailed explanation-1: -As the sodium ions rush back into the cell, they add positive charge to the cell interior, and change the membrane potential from negative to positive. Once the interior of the cell becomes more positively charged, depolarization of the cell is complete, and the channels close again.

Detailed explanation-2: -What happens to the charges on inside and outside the cell when the cell membrane is stimulated? The outside of the cell changes to a negative charge and the inside of the cell turns to a positive charge for a short period of time.

Detailed explanation-3: -A neuron at rest is negatively charged: the inside of a cell is approximately 70 millivolts more negative than the outside (−70 mV, note that this number varies by neuron type and by species).

Detailed explanation-4: -Depolarization is caused by a rapid rise in membrane potential opening of sodium channels in the cellular membrane, resulting in a large influx of sodium ions. Membrane Repolarization results from rapid sodium channel inactivation as well as a large efflux of potassium ions resulting from activated potassium channels.

Detailed explanation-5: -In most neurons this potential, called the membrane potential, is between −60 and −75 millivolts (mV; or thousandths of a volt; the minus sign indicates that the inner surface is negative). When the inside of the plasma membrane has a negative charge compared to the outside, the neuron is said to be polarized.