BPK 205 Lecture Notes - Lecture 21: Vasodilation, Skeletal Muscle, Flow Velocity
4 Nov 2017
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Document Summary
The cardiovascular system transports: substances entering the body -> o2, water, nutrients, substances leaving the body -> metabolic, waste, heat, co2, substances moving around the body -> waste, hormones, immune cells, antibodies. Arteries are very elastic and act as a pressure reservoir that maintains blood flow during ventricular relaxation: maintains blood pressure. Veins act as expandable volume reservoirs (to increase or decrease the effective circulating volume) Arterioles are site of variable resistance due to changes in diameter: regulates blood pressure. Exchange between blood and tissue takes place at capillaries since they are very thin and leaky (made of 1 layer of epithelium) Easily collapse or expand to maintain venous return. Fairly muscular and highly distensible: *composition mirrors the function. Blood flow (q) = flow rate = volume/time = cardiac output (l/min) Variable blood flow distribution to tissues is possible due to parallel arrangement of arterioles: variability depends on organ needs, ex.
