Consider the following statements regarding the human nervous system and action potentials: 1. Depolarization of a neuron membrane occurs due to the rapid influx of sodium ions through voltage-gated sodium channels. 2. Repolarization is achieved primarily through the efflux of potassium ions out of the intracellular fluid. Which of the statements given above is/are correct?

💡 Solution & Explanation

An action potential begins with the opening of voltage-gated sodium channels, permitting a rapid influx of sodium ions that depolarizes the membrane potential. Repolarization quickly follows as sodium channels inactivate and voltage-gated potassium channels open, allowing potassium ions to flow outward and restore resting negative charge inside the cell. The sodium-potassium pump subsequently restores baseline ionic distribution across the membrane. Resting membrane potential in typical neurons is around minus seventy millivolts.