| diuretics, osmotic | Diuretics that are filtered at the glomerulus and reabsorbed in the renal tubule only to a limited extent. They thus increase the amount of osmotically active solute in the urine and a corresponding increase in urine volume. These compounds also increase the osmolality of plasma, thereby increasing the diffusion of water from the intraocular and cerebrospinal fluids; they can be used for reducing the pressure and volume of these fluids. (12 Dec 1998) |
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| iso-osmotic | <physiology> Having the same total osmotic pressure or osmolality as another fluid (ordinarily intracellular fluid); such a fluid is not isosmotic if it includes solutes that freely permeate cell membranes. Synonym: iso-osmotic. (05 Mar 2000) |
| osmotic | <chemistry> Pertaining to or of the nature of osmosis (= the passage of pure solvent from a solution of lesser to one of greater solute concentration when the two solutions are separated by a membrane which selectively prevents the passage of solute molecules, but is permeable to the solvent). (18 Nov 1997) |
| osmotic diuresis | Diuresis due to a high concentration of osmotically active substances in the renal tubules (e.g., urea, sodium sulfate), which limit the reabsorption of water. (05 Mar 2000) |
| osmotic diuretics | Drugs, such as mannitol, which by their osmotic effects retain water during urine formation and thus dilute electrolytes in the urine, making resorption less efficient; they promote the elimination of water and electrolytes in the urine. (05 Mar 2000) |
| osmotic fragility | The susceptibility, or lack of resistance, of erythrocytes to haemolysis when exposed to increasingly hypotonic saline solutions. (12 Dec 1998) |
| osmotic nephrosis | Swelling of renal tubular epithelium associated with glomerular filtration of sugars and dextrose; the swelling is due to formation of cytoplasmic vesicles by pinocytosis, and is reversible, probably with no dysfunction, when produced by glucose or mannitol. (05 Mar 2000) |
| osmotic pressure | See: osmosis. The pressure required to prevent osmotic flow across a semi permeable membrane separating two solutions of different solute concentration. Equal to the pressure that can be set up by osmotic flow in this system. (18 Nov 1997) |
| osmotic shock | Passage of solvent into a membrane bound structure due to osmosis, causing rupture of the membrane. A method of lysing cells or organelles. (18 Nov 1997) |
| effective osmotic pressure | That part of the total osmotic pressure of a solution that governs the tendency of its solvent to pass across a boundary, usually a semipermeable membrane; it is commonly represented by the product of the total osmotic pressure of the solution and the ratio (corrected for activities) of the number of dissolved particles that do not permeate the bounding membrane to the total number of particles in the solution; equivalent in meaning to tonicity; commonly expressed in equivalent units of osmolality rather than pressure per se. (05 Mar 2000) |
| action potential | <physiology> The sequential, electrochemical polarization and depolarisation that travels across the membrane of a nerve cell (neuron) in response to stimulation (touch, pain, cold, etc.) (09 Oct 1997) |
| bioelectric potential | Electrical potential's occurring in living organisms. (05 Mar 2000) |
| biological hazard potential | <radiobiology> Measure of the hazard posed by a given quantity of radioactive material in which the variation in biological effects of the various elements are accounted for. See: integrated biological hazard potential. (21 Mar 1998) |
| biotic potential | <biology, ecology> The potential growth a population of living things can expect if it were living under ideal environmental circumstances. (19 Jan 1998) |
| body surface potential mapping | Recording of regional electrophysiological information by analysis of surface potentials to give a complete picture of the effects of the currents from the heart on the body surface. It has been applied to the diagnosis of old inferior myocardial infarction, localization of the bypass pathway in wolff-parkinson-white syndrome, recognition of ventricular hypertrophy, estimation of the size of a myocardial infarct, and the effects of different interventions designed to reduce infarct size. The limiting factor at present is the complexity of the recording and analysis, which requires 100 or more electrodes, sophisticated instrumentation, and dedicated personnel. (12 Dec 1998) |