ANA300Y1 Lecture Notes - Lecture 6: Superior Vena Cava, Subclavian Vein, Tunica Externa
Document Summary
If there are 2 nuclues looking things, the one further from the bv is a pericyte w/in bm of endothelium, but it"s resting and may differentiate to aid with vascular system. Capillaries and blood flow: capillary bed = network, contain collateral arteries (2 arteries that feed into same capillary bed) (e. g around your elbow) from arterial anastomoses (anastamosis. By shunting blood away from surface of body, you keep warm in colder environments (they"re thermoregulators) Vasodilation and vasoconstriction: occurs in large and small vessels (apparently true capillaries don"t have smooth muscle, just endothelium, no, co2 triggers vasodilation (decreased resistance, sympathetic input, circulating epinephrine from adrenal glands alters vascular resistance in arterioles: In most cases, sympathetic surge causes vasoconstriction, increased vascular resistance. (eg. blood leaves skin and gi tract, and goes to smooth muscle) Tissue capillary density: capillary density varies w/ overall metabolic demand of the tissue, the greater the density of capillary beds, the greater the sa for gas exchange.
