- 1. An apparatus for forcing a gas or liquid from or to any part. 2. Any mechanism for using metabolic energy to accomplish active transport of a substance.- calcium p. a membranal protein that can transport calcium ions across the membrane using energy from ATP.- constant infusion p. an electrically driven device for delivery from a reservoir of a constant, often very small, volume of solution over a prolonged period of time.- hydrogen p. molecular mechanism for acid secretion from gastric parietal cells based on the activity of a H+-K+-ATPase.- intraaortic balloon p. an externally actuated and intermittently inflatable balloon placed into the descending aorta and that, on activation during diastole, augments blood pressure and organ perfusion by its pulsatile thrust; then, on deflation, decreases the cardiac work with each systole—the so-called counterpulsation principle—by reducing cardiac afterload.- ion p. a membranal complex of proteins that is capable of transporting ions against a concentration gradient using the energy from ATP.- jet ejector p. a suction p. in which fluid under high pressure is forced through a nozzle into an abruptly larger tube where a high-velocity jet, at a low pressure in accordance with the Bernoulli law, entrains gas or liquid from a side tube opening just beyond the end of the nozzle to create suction; e.g., the p. by which steam is used to evacuate an autoclave, a water aspirator.- proton p. molecular mechanism for the net transport of protons across a membrane; usually involves the activity of an ATPase.- sodium p. a biologic mechanism that uses metabolic energy from ATP to achieve active transport of sodium across a membrane; sodium pumps expel sodium from most cells of the body, sometimes coupled with the transport of other substances, and also serve to move sodium across multicellular membranes such as renal tubule walls.- sodium-potassium p. a 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 from the cytoplasm to the extracellular fluid. The p. transports both ions against large electrochemical potential gradients and maintains the potassium concentration of the cytoplasm far above, and the sodium concentration far below, their extracellular values. The p. 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 ADP plus one inorganic phosphate ion.* * *putative metalloproteinase
* * *pump 'pəmp n1) a device that raises, transfers, or compresses fluids or that attenuates gases esp. by suction or pressure or both2) HEART3) an act or the process of pumping4) an energy source (as light) for pumping atoms or molecules5) a mechanism by which atoms, ions, or molecules are transported across cell membranes see PROTON PUMP, SODIUM PUMP1) to raise (as water) with a pump2) to draw fluid from with a pump3) to transport (as ions) against a concentration gradient by the expenditure of energy4 a) to excite (as atoms or molecules) esp. so as to cause emission of coherent monochromatic electromagnetic radiation (as in a laser)b) to energize (as a laser) by pumping
* * *(pump) 1. an apparatus for drawing or forcing fluids or gases. 2. to draw or force fluids or gases.
Medical dictionary. 2011.