Sodium Pump

(or sodium-potassium pump), in biochemistry, a membrane mechanism that maintains a definite ratio of Na ⁺ and K ⁺ ions in cells by active transport of the ions against electrochemical and concentration gradients. The cells of most tissues contain more K ⁺ ions than Na ⁺ ions, whereas the fluids reaching the tissues (blood, lymph, and intercellular fluid) contain significantly higher concentrations of Na ⁺. A certain number of ions continuously enters and leaves the cells. The passive transport of cations (transfer of ions through the membrane by means of a system of special channels along the electrochemical and concentration gradients) is, on the average, compensated by active ion transport.

The function of the sodium pump is related to the transfer of metabolites into the cells and, in the case of nerve and muscle fibers, is also related to the mechanism of excitation. The active transfer of Na ⁺ from the cell is associated with the transport of K ⁺ in the opposite direction and is accomplished by a special enzyme system, the sodium-potassium transport system, which is stimulated by adenosine triphosphatase localized in the cell membrane. By hydrolyzing adenosine triphosphate (ATP), adenosine triphosphatase liberates energy, which is expended on the active transfer of cations. The working of the sodium pump on the whole depends on the level of cell metabolism.

R. N. GLEBOV

sodium 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 pump

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.

so·di·um pump

(sō'dē-ŭm pŭmp) A biologic mechanism that uses metabolic energy from adenosine triphosphate 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 pump

the mechanism by which sodium is removed from inside a cell. When occurring in the axon of a neurone, the pump helps to establish the RESTING POTENTIAL. It is also involved in the transfer of salt in the LOOP OF HENLE. The process requires energy from respiration and is an active process; the energy is derived from breaking down ATP. Sodium pumps occur in all cells and should, perhaps, be referred to as sodium/potassium pumps, because potassium ions move into the cell as sodium ions move out. However, cell membranes are more permeable to potassium ions than to sodium ions, so the former diffuse out faster than sodium diffuses in and sodium is also pumped out faster than potassium is pumped in. This, together with the mobility of large negative organic ions to move out of the axon, maintains the resting potential.

so·di·um pump

(sō'dē-ŭm pŭmp) Biologic mechanism that uses metabolic energy from adenosine triphosphate to achieve active transport of sodium across a membrane.

单词	sodium pump
释义	sodium pump so′dium pump` n. an energy-consuming mechanism in cell membranes that transports sodium ions across the membrane, in exchange for potassium ions or other substances. [1960–65] Sodium Pump Sodium Pump (or sodium-potassium pump), in biochemistry, a membrane mechanism that maintains a definite ratio of Na ⁺ and K ⁺ ions in cells by active transport of the ions against electrochemical and concentration gradients. The cells of most tissues contain more K ⁺ ions than Na ⁺ ions, whereas the fluids reaching the tissues (blood, lymph, and intercellular fluid) contain significantly higher concentrations of Na ⁺. A certain number of ions continuously enters and leaves the cells. The passive transport of cations (transfer of ions through the membrane by means of a system of special channels along the electrochemical and concentration gradients) is, on the average, compensated by active ion transport. The function of the sodium pump is related to the transfer of metabolites into the cells and, in the case of nerve and muscle fibers, is also related to the mechanism of excitation. The active transfer of Na ⁺ from the cell is associated with the transport of K ⁺ in the opposite direction and is accomplished by a special enzyme system, the sodium-potassium transport system, which is stimulated by adenosine triphosphatase localized in the cell membrane. By hydrolyzing adenosine triphosphate (ATP), adenosine triphosphatase liberates energy, which is expended on the active transfer of cations. The working of the sodium pump on the whole depends on the level of cell metabolism. R. N. GLEBOV sodium 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 pump 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. so·di·um pump (sō'dē-ŭm pŭmp) A biologic mechanism that uses metabolic energy from adenosine triphosphate 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 pump the mechanism by which sodium is removed from inside a cell. When occurring in the axon of a neurone, the pump helps to establish the RESTING POTENTIAL. It is also involved in the transfer of salt in the LOOP OF HENLE. The process requires energy from respiration and is an active process; the energy is derived from breaking down ATP. Sodium pumps occur in all cells and should, perhaps, be referred to as sodium/potassium pumps, because potassium ions move into the cell as sodium ions move out. However, cell membranes are more permeable to potassium ions than to sodium ions, so the former diffuse out faster than sodium diffuses in and sodium is also pumped out faster than potassium is pumped in. This, together with the mobility of large negative organic ions to move out of the axon, maintains the resting potential. so·di·um pump (sō'dē-ŭm pŭmp) Biologic mechanism that uses metabolic energy from adenosine triphosphate to achieve active transport of sodium across a membrane. ThesaurusSeepump
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sodium pump

so′dium pump`

Sodium Pump

Sodium Pump

sodium pump

pump

so·di·um pump

so·di·um pump

sodium pump

so·di·um pump