sodium-potassium pump

sodium-potassium pump

n.

The enzyme-based mechanism that maintains correct cellular concentrations of sodium and potassium ions by removing excess ions from inside a cell and replacing them with ions from outside the cell.

---

sodium-potassium pump,

a protein that transports sodium and potassium ions across cell membranes against their concentration gradients. Sodium is normally moved from the inside of the cell, where its concentration is low, to the extracellular fluid, where its concentration is much higher. Potassium is moved in the opposite direction. Energy for the pump is obtained from the hydrolysis of adenosine triphosphate. See also calcium pump, electrolyte balance.