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19 Cards in this Set
- Front
- Back
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what are the three majors of vessels |
arteries veins capillaries |
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arteries |
they carry blood away from heart |
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veins |
carry blood towards the heart |
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capillaries |
contact tissue cells and directly serve cellular needs |
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what are the three tunics in veins and arteries? |
1.tunica interna 2. tunica media 3. tunica externa |
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what are capillaries composed of? |
endothelium with little basal lamina |
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lumen |
central blood containing space surrounded by tunics |
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tunica interna |
endothial layer that lines lumen of all vessels |
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tunica media and also what does it control? |
smooth muscle and elastic fiber layer, regulated by sympathetic nervous system -controls vasoconstriction and vasodilation |
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tunica externa |
collagen fibers that protect and reinforce vessels |
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elastic arteries |
thick walled arteries near the heart; aorta and its major branches |
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characteristics of elastic arteries |
large lumen which allows lower resistance contains elastin in all 3 tunics transport blood to the muscular arteries allow blood to flow fairly continuously |
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muscular arteries |
deliver blood to body organs |
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characteristics of muscular arteries |
thick tunica media with more smooth muscle active in vasoconstriction carries blood to specific organs |
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arterioles |
smallest arteries; lead to capillary beds mostly smooth muscle controls flow into capillary bed controls blood flow and constriction |
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capillaries |
smallest of blood vessels |
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characteristics of capillaries |
thin tunica externa, no muscle or connective tissue involved in gas exchange, nutrient waste exchange and delivery |
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3 types of capillaries |
continuous, fenestrated, sinusoids |
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how is blood flow in capillaries regulated |
precapillary sphincter |
