Following the spike of an action potential, the return to resting membrane potential is facilitated by A) Na⁺ ions moving into the cell through open Na⁺ channels. B) K⁺ ions moving into the cell through K⁺ channels. C) the closing of Cl^- ion channels. D) inactivation of leak channels. E) the opening of voltage-gated K⁺ channels.

Question

Quizplus · Accepted Answer

The opening of voltage-gated K⁺ channels is responsible for the return to resting membrane potential after an action potential. This allows K+ ions to move out of the cell, balancing the positive charge from the influx of Na+ during the action potential. Choice A is not correct because Na+ ions move out of the cell during repolarization, not into the cell. Choice B is not correct because K+ ions are already in high concentration inside the cell, so the movement of K+ into the cell would not help return to resting membrane potential. Choice C is not correct because the closing of Cl- channels would have no effect on the movement of K+ ions to return the membrane potential to resting. Choice D is not correct because inactivation of leak channels has no effect on the movement of K+ ions and returning to resting membrane potential.

Following the Spike of an Action Potential, the Return to Resting