KINE 1P90 Lecture Notes - Lecture 14: Stroke Volume, Collagen, Lymphatic Vessel
9 Mar 2016
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Document Summary
Tissues always have same blood low (not more/less during systole/diastole) Enhance difusion and exchange materials between blood and issues in body. Difusing molecules have shirt distance to travel between blood and surrounding issue. Capillary walls are thin (single endothelial cell layer) Narrow lumen (rbc squeeze through in single ile) Extensive capillary branching (no cell is farther than 0. 01 cm from a capillary) Capillaries are suited to enhance difusion and exchange materials between blood and issues of body. Enormous surface area but only holding 5% of total blood volume at any given ime. Difusion across walls depend on permeability of wall at any given moment. This permeability will difer from organ to organ and may be enhanced (histamine) Pores from between endothelial cells and allow passage of small water-soluble substances. Protein hormones may be moved across capillary wall by vesicular transport. Capillaries branch either directly from an arteriole or from a metarteriole. Flow through metarterioles is controlled by precapillary sphincters.
