| 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) |
| topping and back pressure turbine | Turbines which operate at exhaust pressure considerably higher than atmospheric (noncondensing turbines). These turbines are often multistage types with relatively high efficiency. (05 Dec 1998) |
| transducers, pressure | Transducers that are activated by pressure changes, e.g., blood pressure. (12 Dec 1998) |
| transmural pressure | Pressure across the wall of a cardiac chamber or of a blood vessel. In the heart, transmural pressure is the resultant of the intracavitary pressure minus the extracavitary (i.e., pericardial) pressure and is the distending, i.e., true filling, pressure of the cardiac chamber of measurement when this is done during diastole. Since the pericardial pressure normally approximates zero, the filling pressure (usually equal to ventricular diastolic mean pressure), obviating the complexities of measuring pericardial pressure. (05 Mar 2000) |
| transpulmonary pressure | The difference between the pressure of the respired gas at the mouth and the pleural pressure around the lungs, measured when the airway is open; thus, it includes not only the transmural pressure of the lung but also any drop in pressure along the tracheobronchial tree during flow. (05 Mar 2000) |
| transthoracic pressure | The pressure in the pleural space measured relative to the pressure of the ambient atmosphere outside the chest; the transmural pressure across the chest wall. (05 Mar 2000) |
| zero end-expiratory pressure | Airway pressure which, at the end of expiration, equals atmospheric pressure. (05 Mar 2000) |
| urethral pressure profile | The continual recording of pressure through a hole in the side of a small catheter as it is pulled (at a constant rate while either water or a gas is infused through the hole) from a point within the bladder, through the vesical neck, and down the entire urethra; a form of resistance measurement which gives a tracing indicative of the functional length of the urethra and the points of maximal urethral resistance. (05 Mar 2000) |
| french pressure cell | A device used to cause cells to burst (or lyse) with hydrostatic pressure. The cells are suddenly forced into low pressure after being in high pressure. (09 Oct 1997) |
| leak point pressure | Storage pressure in bladder at which leakage occurs passively, usually in patients with neuropathic bladder. (05 Mar 2000) |
| left atrial pressure | <radiology> 15-20 mm Hg redistribution 20-25 interstitial oedema 25-30 airspace oedema (12 Dec 1998) |
| low-pressure | Having, employing, or exerting, a low degree of pressure. Low-pressure steam engine, a steam engine in which low steam is used; often applied to a condensing engine even when steam at high pressure is used. See Steam engine. Source: Websters Dictionary (01 Mar 1998) |