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The arm–leg (blood pressure) gradient is the difference between the blood pressure measured in the arms and that measured in the legs. It is normally less than 10 mm Hg, [ 36 ] but may be increased in e.g. coarctation of the aorta .
This makes a pressure gradient between the infra- and supradiaphragmatic parts of v. cava inferior, "pulling" the blood towards the right atrium and increasing venous return. Vena cava compression : An increase in the resistance of the vena cava, as occurs when the thoracic vena cava becomes compressed during a Valsalva maneuver or during late ...
Plane Poiseuille flow is flow created between two infinitely long parallel plates, separated by a distance h with a constant pressure gradient G = − dp / dx is applied in the direction of flow. The flow is essentially unidirectional because of infinite length. The Navier–Stokes equations reduce to
Coronary perfusion pressure (CPP) refers to the pressure gradient that drives coronary blood pressure. The heart's function is to perfuse blood to the body; however, the heart's own myocardium (heart muscle) must, itself, be supplied for its own muscle function.
The flow profiles was first derived by John R. Womersley (1907–1958) in his work with blood flow in arteries. [1] The cardiovascular system of chordate animals is a very good example where pulsatile flow is found, but pulsatile flow is also observed in engines and hydraulic systems, as a result of rotating mechanisms pumping the fluid.
The Womersley numbers tend to 1 at the level of the terminal arteries. In the arterioles, capillaries, and venules the Womersley numbers are less than one. In these regions the inertia force becomes less important and the flow is determined by the balance of viscous stresses and the pressure gradient. This is called microcirculation. [4]
In the life sciences, mass flow, also known as mass transfer and bulk flow, is the movement of fluids down a pressure or temperature gradient. [1] As such, mass flow is a subject of study in both fluid dynamics and biology. Examples of mass flow include blood circulation and transport of water in vascular plant tissues. Mass flow is not to be ...
Jean Louis Marie Poiseuille is credited with developing the theory of Poiseuille's Flow. It describes the relationship between flow and pressure gradient in long tubes with constant cross section. [2] Otto Frank published the "Fundamental form of the arterial pulse," which contained his "Windkessel theory" of circulation in 1890.