The primary site of this exchange is capillaries and

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Unformatted text preview: he primary site of this exchange is capillaries and small post-capillary venules (sometimes grouped together and called "exchange vessels"). Several mechanisms are involved in this exchange; however, the most important are bulk flow and diffusion. The rate of exchange, in either direction, is determined by physical factors: hydrostatic pressure, oncotic pressure, and the physical nature of the barrier separating the blood and the interstitium of the tissue (i.e., the permeability of the capillary wall). There are two important and opposing hydrostatic forces: capillary hydrostatic pressure (PC) and tissue hydrostatic pressure (PT). Because PC is normally much greater than PT, the net hydrostatic pressure gradient across the capillary is positive, meaning that hydrostatic forces are driving fluid out of the capillary and into the interstitium. There are also two opposing oncotic pressures influencing fluid exchange: capillary plasma oncotic pressure (pC) and tissue (interstitial) oncotic pressure...
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This note was uploaded on 04/18/2008 for the course PHYS 1010 taught by Professor Thompson during the Fall '07 term at New York Medical College.

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