KINE 1P90 Lecture Notes - Lecture 9: Cardiac Muscle, Elastin, Sympathetic Nervous System

• School: Brock University
• Department: Physical Education and Kinesiology
• Course: KINE 1P90
• Professor: Nota Klentrou

Document Summary

Extensive capillary branching (no cell is farther than 0. 01cm from a capillary) Capillary walls are thin (a single layer of endothelial cells) The lumen of each capillary is very narrow (red blood cells must squeeze through in. Capillaries are ideally suited to 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 the surrounding tissues single file) The diffusion of across capillary walls depends on the permeability of the wall to any given material. This permeability will differ from organ to organ, and may be enhanced (ex. 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 either directly from an arteriole or from a metarteriole. Flow through metarterioles is controlled by precapillary sphincters. Only 10% of precapillary sphincters are open in resting muscle.