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Anatomy
Blood Vessels + Circulation
10
Anatomy
Not Applicable
02/16/2004

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Cards

Term
flow of blood vessels
Definition
arteries-arterioles-capillaries-venules-veins
Term
what are the walls composed of three layer?
Definition
endothelium: innermost layer, very smooth
smooth muscle: middle layer, sympathetic innervation produces vasoconstriction(lack of symp. act produces vasodilation), thickest in arteries; elastin fibers also found btwn muscle cells
collagen fibers: outer layer, also contains nerves fibers
Term
what are the three arteries?
Definition
elastic arteries, muscular arteries, and arterioles
Term
elastic arteries?
Definition
aorta & its major branches, pulmonary trunk; large diameter, elastic fibers > smooth muscle; "smooth out" or reduce fluctuation in pressure when ventricles contract not responsive to vasoconstriction(why is this important)
Term
muscular arteries?
Definition
deliver blood to specific organs & muscles(carotids, brachial) elastic fibers=smooth muscle
Term
arterioles?
Definition
small diameter
elastic fibers < smooth muscle
important in regulating blood pressure & capillary blood flow
Term
what are the walls of the capillaries like?
Definition
walls are single layer of endothelial cells w/ small gaps btwn cells
-gas exchange & diffusion of nutrients occurs through gaps
Term
what's the blood-brain barrier in the capillaries?
Definition
brain capilaries have no gaps so diffusion can only occur across endothelial cell membrane that forms networks called capillary beds
Term
what do the precapillary sphincters do in the capillaries?
Definition
controls flow through capillaries, determined by tissue needs(ex: muscles, GI tract)
Term
what does the vascular shunt vessel do in the capillaries?
Definition
directs connection of arteriole & venule, used when capillary bed in closed
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