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sodium-potassium pump
so·di·um-po·tas·si·um pump S0533950 (sō′dē-əm-pə-tăs′ē-əm)n. A mechanism of active transport that moves potassium ions into and sodium ions out of a cell.EncyclopediaSeepumpsodium-potassium pump
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 tube" >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.so·di·um-po·tas·si·um pumpa membrane-bound transporter found in nearly all mammalian cells that transports potassium ions into the cytoplasm from the extracellular fluid while simultaneously transporting sodium ions out of the cytoplasm to the extracellular fluid. The pump transports both types of ions against large electrochemical potential gradients and maintains a much higher concentration of potassium (and a much lower concentration of sodium) in the cytoplasm than exists outside the cell. The pump is an enzyme that transports two potassium ions in exchange for three sodium ions in a reaction driven by hydrolysis of one molecule of ATP to form ATP plus one inorganic phosphate ion. Synonym(s): sodium-potassium ATPasesodium-potassium pump (sō′dē-əm-pə-tăs′ē-əm)n. A mechanism of active transport that moves potassium ions into and sodium ions out of a cell.so·di·um-po·tas·si·um pump (sō'dē-ŭm pŏ-tas'ē-ŭm pŭmp) A membrane-bound transporter that maintains high potassium and low sodium intracellular concentrations relative to the extracellular medium. This exchange is accomplished at the expense of cellular energy in the form of adenosine triphosphate. |