Arterioles small precapillary resistance vessels 10 50

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Unformatted text preview: nules, and terminal lymphatic vessels. Arterioles Small precapillary resistance vessels (10-50 ) composed of an endothelium surrounded by one or more layers of smooth muscle cells. Richly innervated by sympathetic adrenergic fibers and highly responsive to sympathetic vasoconstriction via both a 1 and a 2 postjunctional receptors. Represent a major site for regulating systemic vascular resistance. Rhythmical contraction and relaxation of arterioles sometimes occurs (i.e., spontaneous vasomotion). Primary function within an organ is flow regulation, thereby determining oxygen delivery and the washout of metabolic by-products. Regulate, in part, capillary hydrostatic pressure and therefore influence capillary fluid exchange. Capillaries Small exchange vessels (6-10 ) composed of highly attenuated (very thin) endothelial cells surrounded by basement membrane no smooth muscle. Three structural classifications: Continuous (found in muscle, skin, lung, central nervous system) basement membrane is continuous and intercellu...
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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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