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20 Cards in this Set
- Front
- Back
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tunica externa (adventitia) |
-outermost layer of vein/artery covering -elastic and laminar fibers (artery) |
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tunica media |
-middle most layer vein/artery covering -thickest layer -smooth muscle fibers and elastic muscle fibers --(thicker and more elastic in artery) |
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tunica interna (intima) |
-innermost layer of vein/artery covering -endothelium: nonstick layer -basement membrane: keeps cells properly attached -internal elastic lamina
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vessel size |
-closer to heart= thicker in diameter -structure and function can change as one moves throughout the cardiovascular system |
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elastic (conducting) arteries |
-near the heart -largest in diameter, thickest walls -D: 1.5 cm T: 1mm -more elastic fibers -slightly less smooth muscle -lose elasticity with aging |
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aorta and elastic arteries |
-aorta: largest blood vessel -can vasoconstrict or vasodialate very easily -WIndkessel effect: large arteries expand to absorb force of each pressure wave, then release with elastic recoil -with aging, arteries have less expansion and recoil -elastic artery: D=1.5cm T=1.0mm |
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muscular (distributing) arteries |
-tunica media very thick, more smooth muscle -delivers blood to most organs -fewer elastic fibers -D=6.0mm T=1.0mm |
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arterioles |
-distributes blood within organs -wall composition varies depending on position, less smooth muscle and more elastic fibers distal from the heart -regulate flow from arteries from capillary beds -can vary resistance of flow by changing diameter -sites for BP regulation -better capable to exchange nutrients -D=37.0um T=6.0um (um: miore meter) |
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capillaries |
-microcirculation, between arteries and veins -in most every body tissue -higher metabolic activity, more capillaries -skeletal muscle has most (> 600/mm2) -epidermis and tooth enamel have none -exchange of nutrients and waste -one layer of SSE cells -endothelial cells prevent blood from sticking to walls |
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continuous capilaries |
- continuous lining of endothelial cells except for the clefts between cells -very tight junctions between cells -cells overlap each other -most abundant in body -slower blood flow |
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fenestrated capillaries |
-fenestrations "windows/holes" are not true holes but just super compressed membrane to allow greater fluid transmission and flow -glomerular capillaries in the kidneys -"holes" get rid of waste while still allowing blood flow |
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sinusoid capillaries |
-wider intercellular gaps -allowing increasing exchange with surrounding tissues -may have a larger diameter -more irregular cross section -liver, blood marrow, lymphoid tissue, endocrine glands -intercellular clefts allow WBCs to migrate in and out |
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capillary beds |
-flow regulated by smooth muscle "valves" |
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metarterioles |
-from arterioles to venules through capillary bed -allows flow within capillary bed without flowing through actual capillaries |
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true capillaries |
-pre capillary sphincter: ring of smooth muscle, open/close to control flow, regulated by chemicals -intermittent vasomotion, open for flow 5-10 times each min |
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venules |
-collect blood from capillary beds to take to veins -carry deoxygenated blood -structure changes with distance to the heart -become more vessel like as it moves away from capillaries - D: 20.0 um T:1.0um |
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veins |
-interna thinner than arteries -media much thinner, less smooth muscle -thick externa, more collagen fibers -have vavles, but differ from the heart valves -diameter doesn't change as much, low pressure -high compliance: change volume easily with small change in pressure
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varicose veins |
-lost compliance -unable to recoil and become visible |
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blood stystem
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-at rest, 60% of volume is in veins and venules
-venous system serves as reservoirs for blood, particularly in veins of abdominal organs and skin |
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nervous system and the blood |
-the NS regulates blood distribution -vasoconstriction and vasodilation -diverts blood to areas with increased metabolic needs; like after eating or exercising |
