Which cellular mechanism moves sodium and potassium ions across the membrane to enable nerve impulse transmission?

• A. Action Potential
• B. Ion Channel
• C. Sodium Potassium Pump
• D. Neurotransmitter

Answer: (C)

Maintaining ion gradients across the neuron's membrane is essential for nerve signaling. The sodium-potassium pump uses ATP to move three sodium ions out of the cell and two potassium ions in, which keeps the inside of the neuron more negative and preserves a high extracellular Na+ and a high intracellular K+ concentration. This gradient creates the electrochemical force that drives ions when channels open during signaling, and it also helps quickly restore the resting state after an impulse. While the rapid spike in voltage during an impulse is carried by ion channels, the pump sustains the gradients needed for that process and reestablishes them afterward, making it the critical mechanism for enabling nerve impulse transmission.