| 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) |
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| 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) |
| reduced enamel epithelium | The several layers of the enamel organ remaining on the enamel surface after formation of enamel is completed. Synonym: reduced enamel epithelium. (05 Mar 2000) |
| reduced eye | A simplified design of the ocular optical system, represented as having a single refracting surface and a uniform index of refraction; a model based on this concept is used in retinoscopy and ophthalmoscopy. (05 Mar 2000) |
| reduced glutathione | Glutathione acting as a hydrogen donor. (05 Mar 2000) |
| reduced haematin | 1. <biochemistry> Compounds of iron complexed in a porphyrin (tetrapyrrole) ring that differ in side chain composition. Haems are the prosthetic groups of cytochromes and are found in most oxygen carrier proteins. 2. <prefix> haem-, eaning relating to blood. Origin: G. Haima (21 Jun 2000) |
| reduced haemoglobin | The form of Hb in red blood cells after the oxygen of oxyhemoglobin is released in the tissues. (05 Mar 2000) |
| reduced interarch distance | An occluding vertical dimension which results in an excessive interocclusal distance when the mandible is in rest position, and in a reduced interridge distance when the teeth are in contact. (05 Mar 2000) |
| Listing's reduced eye | A representation that simplifies calculations of retinal imagery: radius of anterior refracting surface, 5.1 mm; total length, 20 mm; distance of nodal point to retina, 15 mm. (05 Mar 2000) |
| 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) |
| 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) |