How the sodium-potassium pump sets the resting potential
The Na/K-ATPase pump sits in the cell membrane and uses energy from ATP to push sodium ions out of the cell and potassium ions in, moving each against its concentration gradient. The result is high sodium outside and high potassium inside, an electrochemical imbalance that the cell maintains continuously. This stored difference creates the negative resting membrane potential found in nerve and muscle cells.
Because the pump moves three sodium out for every two potassium in, it also contributes directly to the charge separation, making it both a gradient builder and a small generator of membrane voltage.
Turning the gradient into nerve and muscle signals
The gradients the pump maintains are the stored energy that nerve impulses and muscle contractions draw on. When a cell is triggered, channels open and ions rush down these gradients, briefly reversing the membrane voltage to produce an action potential, after which the pump restores the resting state. This cycle underlies every heartbeat, movement, and nerve signal.
Disturbances in sodium or potassium levels can therefore affect nerve and muscle function. This is general educational information, not medical advice; electrolyte abnormalities can be serious and should be assessed by a qualified professional.