The relative concentrations of Na⁺ and K⁺ remain constant during a single action potential,despite movement of these ions across the membrane,because
A)they cross back immediately through recovery channels.
B)they are pumped back across using the Na⁺/K⁺ ATPase pump.
C)they are forced back across the membrane as the action potential moves away.
D)the refractory periods do not end until all ions have been returned to their original areas.

Question

Quizplus · Accepted Answer

The movement of Na⁺ and K⁺ across the membrane during an action potential is facilitated by ion channels, but the relative concentrations of these ions remain constant because they are actively pumped back across the membrane by the Na⁺/K⁺ ATPase pump. This prevents a buildup of either ion on one side of the membrane and helps maintain the resting membrane potential. Recovery channels do not exist, and the refractory periods do not impact the movement of ions during an action potential.

The Relative Concentrations of Na⁺ and K⁺ Remain Constant During