INTEGBI 131 Lecture Notes - Lecture 13: Tunica Externa, Tunica Intima, Vasa Vasorum
6 Jan 2020
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Document Summary
Arteries: blood away from heart (in > out) lumen, tunica intima (endothelium- simple squamous, subendothelial, internal elastic membrane), tunica media (smooth muscle, elastic fibers, external elastic mem / cause vaso-constriction/dilation), tunica externa (w/collagen fibers) Capillaries: smallest vessels & site of exchange (molecules, fluid) Elastic arteries (widest, conduct blood ) > muscular arteries ( distribute blood) > arterioles. Elastic arteries (aka conducting arteries) : aorta & major branches, high elastin content , vasa vasorum : network of small blood vessels that supply walls (tunica externa) of large vessels (ie- elastic arteries) w/nutrients ( vessels of vessels ) Muscular arteries: distal to elastic^, most arteries, thick tunica media w/smooth muscle & elastin fibers~ & internal & external elastic membranes that dampen pulsatile pressure from heartbeat. Arterioles: (only larger arterioles w/all 3 tunics), diameter controlled by local tissue factors &/or ans. Capillaries: rbc single file, site-specific functions ( lungs & other tissues - exchange o2 &
