| 释义 |
DictionarySeepumpcalcium pump
calcium pump[¦cal·se·əm ‚pəmp] (cell and molecular biology) An enzyme that uses the energy generated by the hydrolysis of adenosine triphosphate (ATP) to move calcium ions out of the cytoplasm or, in the case of muscle cells, from the cytoplasm to the sarcoplasmic reticulum. Also known as Ca2+ATPase. calcium 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.cal·ci·um pumpa membranal protein that can transport calcium ions across the membrane using energy from ATP.calcium pump A calcium-pumping enzyme which is present in high concentrations (up to 90%) in the membrane of sarcoplasmic reticulum and activated by cATPase, which reduces cytoplasmic Ca2+, ends muscle contraction and allows muscle relaxation.cal·ci·um pump (kal'sē-ŭm pŭmp) A membranal protein that can transport calcium ions across the membrane using energy from ATP. |