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.

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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.

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pump [pump]

1. an apparatus for drawing or forcing liquid or gas.

2. to draw or force liquids or gases.

blood pump a machine used to propel blood through the tubing of extracorporeal circulation devices.

breast pump a pump for taking milk from the breast.

calcium pump the mechanism of active transport of calcium (Ca²⁺) across a membrane, as of the sarcoplasmic reticulum of muscle cells, against a concentration gradient; the mechanism is driven by hydrolysis of ATP.

enteral feeding pump an infusion pump specifically designed for administration of a solution through a feeding tube.

insulin pump see insulin pump.

intra-aortic balloon pump see intra-aortic balloon pump.

muscle pump compression of veins by the contraction of skeletal muscles, forcing blood towards the heart against the flow of gravity; seen particularly in the deep veins of the lower limbs. Called also venous pump.

Na⁺-K⁺ pump sodium-potassium pump.

proton pump a system for transporting protons across cell membranes, often exchanging them for other positively charged ions.

sodium pump (sodium-potassium pump) the mechanism of active transport driven by the energy generated by Na⁺,K⁺-ATPase, by which sodium (Na⁺) is extruded from a cell and potassium (K⁺) is brought in, so as to maintain the low concentration of sodium and the high concentration of potassium within the cell with respect to the surrounding medium. A high concentration of intracellular potassium is necessary for vital processes such as protein biosynthesis, certain enzyme activities, and maintenance of the membrane potential of excitable cells. Called also Na⁺-K⁺ pump.

stomach pump see stomach pump.

venous pump muscle pump.