PHYSL402 Lecture Notes - Lecture 15: Endothelium, Central Venous Catheter, Total S.A.
7 Nov 2016
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Sympathetic nerves primarily innervated arterioles but also venous system: central venous p and maintain adequate co. Sm of most arterioles (except those in brain) ahs alpha adrenergic r. 1 cell layer (usually endothelial cells; line all cells) Small diffusion barrier: easy diffusion back and forth. Site of exchange b/w blood and tissue: are in close proximity to cells. Protein free plasma moves through the capillaries (pores not large enough) Even through not suppose to get protein movement, but can occur (ie transcytosis) Bulk flow = movement of water + solutes. Forces for bulk flow: hydrostatic and osmotic p. Hydrostatic p gradient = force due to fluid. Osmotic p = osmotic f exerted on water by non-permeating solutes. Direction of starling forces across a capillary wall. Pcap = capillary hydrostatic p (most subj to reg) Always going to be a gradient that will favor either reabsorption or filtration. Capillary hydrostatic p most subject to homeostatic regulation.
