BIOL 1119 Lecture Notes - Lecture 32: Osmosis, Venule, Renal Function
4 Apr 2017
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Excrete just enough water and inorganic ions to keep amounts of these materials within narrow homeostatic range. Filters blood plasma: eliminates wastes, returned useful substance to blood. Regulates: osmolality of body fluids, blood volume, bp, carbon dioxide levels, acid-base balance. Metabolic waste: produced by chemical cellular process. Filtration membrane fenestrations: fenestrated capillaries are for rapid passage of small molecules but still retain more proteins and larger partials, fund where filtration/reabsorption (glomerulus) basement membranes, negatively charged proteoglycan gel that helps hold back particles larger than. Bp builds up backs up : cop is fairly high bc glom filtrate is almost protein free; no significant cop, net effect: filtration. In most blood capillaries, bhp drops low enough at end that net osmosis overrides filtration and the capillaries reabsorb fluid. In the glomerular capillaries, bhp remains high enough throughout capillary that only have filtration the venous. The high blood pressure in the glomeruli makes the kidneys especially vulnerable to hypertension.
