reduction of the resting potential of the nerve membrane so that a nerve impulse is fired. At rest, the inner surface of the nerve fiber is negatively charged and imprermeable to sodium ions. A stimulus temporarily alters the membrane, making it permeable so that potassium leaks out and sodium rushes into the nerve fiber. This mechanism is know as the sodium potassium pump. The reversal of electrical charge, or depolarization creates the nerve impulse. The process then reverses, and the membrane potential is restored, or repolarized.
nerual depolarization mechanism