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The heart is supplied by coronary vessels, and therefore CPP is the blood pressure within those vessels. If pressures are too low in the coronary vasculature, then the myocardium risks ischemia (restricted blood flow) with subsequent myocardial infarction or cardiogenic shock .
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
Mean blood pressure drops over the whole circulation, although most of the fall occurs along the small arteries and arterioles. [35] Gravity affects blood pressure via hydrostatic forces (e.g., during standing), and valves in veins, breathing, and pumping from contraction of skeletal muscles also influence blood pressure in veins. [32]
Cerebral perfusion pressure, or CPP, is the net pressure gradient causing cerebral blood flow to the brain (brain perfusion).It must be maintained within narrow limits because too little pressure could cause brain tissue to become ischemic (having inadequate blood flow), and too much could raise intracranial pressure (ICP).
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.
This results in much greater LV pressures than the aortic pressures during LV ejection. The magnitude of the pressure gradient is determined by the severity of the stenosis and the flow rate across the valve. Severe aortic stenosis results in reduced ventricular stroke volume due to increased afterload (which decreases ejection velocity)
Because of this, the valve area may be erroneously calculated as stenotic if the flow across the valve is low (i.e. if the cardiac output is low). The measurement of the true gradient is accomplished by temporarily increasing the cardiac output by the infusion of positive inotropic agents, such as dobutamine.
Cardiac physiology or heart function is the study of healthy, unimpaired function of the heart: involving blood flow; myocardium structure; the electrical conduction system of the heart; the cardiac cycle and cardiac output and how these interact and depend on one another.