If you're going to understand how to think about pressures within the circulatory system, though, you'll need to know a few of the not-so-obvious principles of hydrostatics. Hydrostatic pressure is affected only by the density of the fluid, its vertical height above or below a measurement point, and the acceleration due to gravity. If the larger mass of water in the ocean exerts greater pressure than the smaller mass of water in your vertical pipe, then you should see water perpetually flowing through the pipe and rising higher than sea level. Continual flow doesn't happen in this example for the same reason as described above—hydrostatic pressure is not determined by the shape of the fluid container or the total mass of fluid that it contains. Here, only the vertical distance above the measurement point is important. Now let's apply these principles to the siphon, defined as any fluid-filled conduit that excludes air. The reason for broaching this issue is that the cardiovascular system also obeys the principle of the siphon.
Chapter. 1641 words. Illustrated.
Subjects: Professional Development in Medicine
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