KINE 1P90 Lecture Notes - Lecture 12: Metarteriole, Thoracic Diaphragm, Ultrafiltration
1 Apr 2017
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Document Summary
Kine 1p90- blood vessels and circulation pt. Enhance diffusion and exchange materials between the blood and the tissues of the body. Diffusing molecules have a short distance to travel between the blood and surrounding tissues. Capillary walls are thin (single layer of endothelial cells) The lumen of each capillary is very narrow (red blood cells squeeze through in single file) Extensive capillary branching (cells are close to capillaries) Enormous total surface area, but only holding 5% of the total blood volume at any given time. Blood travels very slowly through the capillary network. The diffusion across capillary walls depends on the permeability of the wall to any material. Pores form between adjacent endothelial cells and allow the passage of small water soluble substances. Protein hormones may be moved across the capillary wall by vesicular transport. Capillaries branch directly from an arteriole or from a metarteriole. The movement of plasma from the capillaries into the interstitial fluid, and vice versa.
