Term
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Definition
the inner layer of a blood vessel
-arteries only have an internal elastic membrane |
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Term
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Definition
the middle layer of a blood vessel, commonly the thickest layer
-contains concentric sheets of smooth muscle in loose connective tissue
-arteries only-exernal elastic membrane separates tunica media from tunica externa |
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Term
| Tunica Externa (tunica adventitia) |
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Definition
the outer layer of a blood vessel
-it is a connective tissue sheath
-in veins, thicker than tunica media, contains elastic fibers and smooth muscle cells |
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Term
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Definition
| contraction of arterial smooth muscle |
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Term
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Definition
| relaxation of arterial smooth muscle |
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Term
| Elastic arteries (conducting arteries) |
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Definition
-large vessels (pulmonary trunk and aorta)
-transport large volumes of blood |
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Term
| Muscular arteries (distribution arteries) |
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Definition
-medium sized
-superficial arteries-pressure points |
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Term
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Definition
-small, little to no tunica externa
-thin or incomplete tunica media
-resistance vessels |
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Term
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Definition
| smallest vessels with thin walls, only vessels that can exchange materials with interstitial fluid |
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Term
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Definition
-Complete endothelial lining, found in all tissues except epithelia and cartilage
-permit diffusion of water, small solutes, and lipid-soluble materials into ISF
-prevent loss of blood cells and plasma proteins |
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Term
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Definition
-have pores in endothelial lining
-permit rapid exchange of water and large solutes between plasma and ISF
-found in choroid plexus, endocrine organs, kidneys, and intestinal tract |
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Term
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Definition
Gaps between adjacent endothelial cells in the liver, spleen, bone marrow, and endocrine organs
-Permit free exchange of water and large plasma proteins |
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Term
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Definition
| -Connect arterioles to venules |
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Term
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Definition
direct capillary connections between arterioles and venules
Wall in initial part of passageway controlled by smooth
muscle segments (metarterioles or precapillary arteriole) |
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Term
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Definition
| multiple arteries that contribute to one capillary bed |
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Term
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Definition
| fusion of 2 collateral arteries |
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Term
| Arteriovenous anastomoses |
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Definition
direct connections between arterioles and venules
-regulated primarily by sympathetic innervation (cardiac centers in medulla oblongata) |
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Term
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Definition
| formation of new blood vessels under direction of vascular endothelial growth factor |
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Term
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Definition
| Contraction and relaxation cycle of capillary sphincters |
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Term
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Definition
very small veins, lack tunica media
collect blood from capillaries |
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Term
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Definition
-Thin tunica media and few smooth muscle cells
-Tunica externa with longitudinal bundles of elastic fibers |
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Term
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Definition
-all 3 tunica layers
-thick tunica externa
-thin tunica media
-include superior/inferior vena cava |
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Term
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Definition
Heart, arteries, capillaries: 30-35% of blood volume
Venous system: 65-70% of blood volume in liver, bone marrow, and skin |
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Term
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Definition
| Ability of a blood vessel to stretch |
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Term
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Definition
| Systemic veins constrict, decreases the amount of blood in the venous system, increases the volume within the arterial system and capillaries |
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Term
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Definition
Folds of tunica intima
Prevent blood from flowing backward
Pressure is so low, cannot overcome gravity
Any compression of vein pushes blood toward heart- improves venous return |
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