NCCAA Re-certification Practice Exam

The sodium-potassium pump's primary function is to actively transport 3 sodium ions (Na+) out of the cell and 2 potassium ions (K+) into the cell. This process is crucial for maintaining the electrochemical gradients across the cell membrane, which are essential for various cellular functions, including nerve impulse transmission and muscle contractions.

By moving a greater number of sodium ions out of the cell compared to potassium ions moving in, the pump creates a net negative charge inside the cell relative to the outside, contributing to the resting membrane potential. This imbalance also helps to control cell volume and prevents cell swelling.

The precision of this transport mechanism is foundational to cellular homeostasis and the overall functioning of excitable tissues, emphasizing the importance of the sodium-potassium pump in both physiological and pathological conditions.