pressure gradient


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Related to pressure gradient: Adverse pressure gradient

pressure gradient

The difference in hydrostatic pressure on either side of a membrane. As the difference in pressures rises, filtration increases from the area of high pressure to the area of low pressure.
See also: gradient

pressure

stress or strain, by compression, expansion, pull, thrust or shear.

arterial pressure
the blood pressure in the arteries.
atmospheric pressure
the pressure exerted by the atmosphere, about 15 lb per square inch (2.17 kPa) at sea level.
capillary pressure
the blood pressure in the capillaries.
central venous pressure (CVP)
see central venous pressure.
cerebrospinal pressure
the pressure of the cerebrospinal fluid, normally 100 to 150 mmHg.
diastolic pressure
the lowest pressure recorded in the arterial blood pressure cycle. Represents the minimal pressure in the left ventricle which can maintain its ejection phase. See also blood pressure.
pressure gauge
a device attached to the outlet of gas tanks to measure internal pressure which indicates the quantity of gas remaining.
pressure gradient
the rate of increase (or decrease) in the magnitude of the pressure being measured.
intracranial pressure (ICP)
see intracranial pressure.
intraocular pressure (IOP)
the pressure exerted against the outer coats by the contents of the eyeball.
pressure load
mean circulatory filling pressure
a measure of the average (arterial and venous) pressure necessary to cause filling of the circulation with blood; it varies with blood volume and is directly proportional to the rate of venous return and thus to cardiac output.
pressure natriuresis
thought to participate in regulating the volume of extracellular fluid levels when the normal neurohumoral mediators are impaired; the increase in water and sodium ion excretions which occur when blood pressure is elevated because of an increase in the circulating blood volume.
pressure necrosis
necrosis of tissue caused by exclusion of circulation by external compression, e.g. in prolonged recumbency, or due to too-tight bandage, collar, harness.
negative pressure
pressure less than that of the atmosphere.
oncotic pressure
the osmotic pressure of a colloid in solution.
osmotic pressure
the potential pressure of a solution directly related to its solute osmolar concentration; it is the maximum pressure developed by osmosis in a solution separated from another by a semipermeable membrane, i.e. the pressure that will just prevent osmosis between two such solutions.
pressure point granuloma
see pressure points (below).
pressure point pyoderma
see pressure points (below).
pressure points
parts of the body subject to pressure when the animal is recumbent, wearing harness or saddlery, or during restraint. Usually bony prominences such as the point of the hock, hip, shoulder, elbow and lateral aspects of limbs. These are predisposed to callus formation, infection pyoderma and granulomas.
positive pressure
pressure greater than that of the atmosphere.
pulse pressure
difference between systolic and diastolic pressures in arteries.
pressure receptors
e.g. the blood pressure receptors in the aortic arch and the carotid sinus.
pressure sore
decubitus ulcer.
systolic pressure
the highest reading in the arterial blood pressure cycle. A reflection of the ejection pressure of left ventricular systole, and the elasticity of the arterial system.
venous pressure
the blood pressure in the veins. See also central venous pressure.
wedge pressure
intravascular pressure as measured by a swan-ganz catheter introduced into the pulmonary artery; it permits indirect measurement of the mean left atrial pressure.
pressure wrap
bandages which apply pressure to underlying tissues; used after trauma to limit the development of edema, and in the management of lymphedema.
References in periodicals archive ?
However, when the flow rate becomes higher than the theoretical chamber flow, that is at the screw speed 40 rpm and flow rate 12 kg/h, the pressure gradient changes the sign and gets negative (Fig.
There is a pressure gradient between the bottom and the top of the log during the vacuum state.
Although the effects are mixed, with less extreme effects of linear interpolation for maximum and mean pressure and more extreme effects of linear interpolation for pressure gradient (hypothesis 3), in all cases, the relative effect was small.
Bhattacharya [9] discussed the flow of immiscible fluids between rigid plates with a time dependent pressure gradient.
The gold standard for diagnosis of renal vein hypertension is renal venography combined with measurement of renocaval pressure gradient, although there is no consensus on criteria for a clear diagnosis.
The fluid is driven by a uniform pressure gradient parallel to the channel plates and the entire flow field is subjected to a uniform inclined magnetic field of strength [H.
5 psig and initial test string influx was observed to 730mRT, upon subsequent pressure gradient survey.
The basic features in the simulation results were as in the conical basin, with the anticyclonic and cyclonic gyres resulting from the balance between the pressure gradient and the Coriolis acceleration.
The shear stress is determined directly from the pressure gradient.
While the calculation of the pressure gradients up-and downstream of the bend is very straight forward, the calculation of the pressure gradient at the U-bend requires one assumption: linear variation of the pressure gradient close to the two extremities of the U-bend.
A pressure gradient develops and accumulation of the gas continues under a constant pressure gradient within the system.