PHGY 210 Lecture Notes - Lecture 9: Interventricular Septum, Interatrial Septum, Cardiac Output
25 Feb 2013
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Document Summary
The pressure that drives blood flow is a change of pressure, called the perfusion pressure, the difference between the two from pin p out. For most organs, it is the pressure of the arteries minus the pressure of the veins. Most of the time, the perfusion pressure is almost the same as the artery pressure, since arterial pressure is many times greater than the venous pressure. Pin = 100 mmhg, p out = 10 mmhg, perfusion pressure = 90mmhg, assume the flow is 10ml per minute. If we then change the pin=500, pout=410, the perfusion pressure is still 90, the flow remains the same at. The flow is only dependent upon the perfusion pressure. The flow = perfusion pressure/ resistance to flow (this differs from one vessel to another). The resistance is measured in pru (peripheral resistance unit), with standard units of mmhg second per ml. Laminar or parabolic flow: fluids, when flowing, is formed of many many layers.
