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12 Cards in this Set
- Front
- Back
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What are basic characteristics of arteries and what are they made up of?
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-carry blood away from heart towards capillary beds
-thicker walls and smaller lumens than veins -more circular than veins 3 layers: Tunica itntima: -endocardium of heart -endothelium with thin basement membrane (basal lamina), internal elastic membrane (lamina) function: -prevention of coagulation -charged particles prevent platelet adhesion and aggregation -produce prostacyclin (inhibition of platelet adhesion -produce NO -release growth factor that promote healing of bone and vascular lesions tunica media: -myocardium of heart -may be smooth layer (small muscular) or elastic (large) -some vessels have external elastic membrane tunica adventititia: -epicardium of heart -outer CT, nerves, lymphatics and vaso vasorum ("vessels of vessels") |
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What are properties of Elastic arteries?
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help to reduce changes in blood pressure associated with heartbeat
Intima - elastic lamina incomplete media - has thick, concentric sheaths of elastic membranes known as fenestrated membranes of elastin tunica adventitita: -vaso vasorum pentrates outer half of media with oxygen and nutrients similar to coronary arteries of heart ex. aorta, brachiocephalic trunk, common carotid, subclavian, most of pulmonary arteries functional properties: -pulmonary arteries, aorta are conducting arteries -large distensibility (compliance) and low resistance to blood flow functions: -conduction of blood w/o loss in pressure -pressure reservoir during diastole |
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What are properties of the muscular artery?
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tunica intima is thin
tunica media has concentrically arranged smooth muscle fibers has two elastic laminas: internal elastic (IEL) between intima and media; external elastic (EEL) outside of media tunica adventitia contains prominent vaso vasorum functional properties: -medium to small arteries -capable of changing diameter (vasoconstriction and vasodilation) -regulate BP by contraction of smooth muscle in tunica media functions: -distributing channels to body tissues ex. radial, femoral, coronary, and cerebral arteries |
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What are Arterioles?
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adventitia is thin and merges with surrounding collagenous fibrous tissue
endothelium is prominent because ateriole is constricted functions: -distribution of blood flow to different tissues -regulation of BP -damping of pulsation |
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What are Capillaries?
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only large enough for RBCs to move in through in single row, biconcave shape is impt
thin and porous wall; moderate resistance to blood flow functions: -exchange vessels between blood and interstitial fluid types: continuous: -found in most tissues -have continuous basement membrane -tight junctions that allow passage of only small water-soluble molecules fenestrated capillaries: -have gaps (fenestrations) which allow passage of macromolecules -found in renal glomeruli, small intestine, ciliary proces sof eye, choroid plexus of brain Sinusoid (discontinuous) capillaries: -large gaps that allow passage of large proteins and blood cells -found in liver, spleen, bone marrow |
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What is the Microcirculatory unit?
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Metarteriole:
-emerges from an arteriole and supplies a network of capillaries (capillary bed) -have smooth muscle that forms precapillary sphincters on arterial side to control blood flow through capillaries -venous end has no smooth muscle; has a throughfare channel that empties into a venule from the arteriole bypassing the capillary network of true capillaries venules |
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What are venules?
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thin wall:
-endothelium, basement membrane - tunica interna, few smooth muscle fibers - tunica media, collagen and elastic fibers - tunica externa numerous pores - emigration of WBC from blood |
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What are veins?
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3 layers:
-thinner tunica interna, media but thicker tunica externa than arteries -no external and internal laminae functions: -valves have -one way flow toards heart -low resistance conduction -storage ("capacitance") - principle blood reservoir for spleen, liver, and skin -regulation of ventricular EDV and ventricular SV (contraction of smooth muscle in response to sympathetic stimulation) vascular sinuses: -no tunica media (smooth muscles) and tunica externa -outside tissues provide support valves occur in venins with more than 2mm diamter, those which drain extremities; projections are composed of fibroelastic tissue |
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What are Varicose veins?
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valvular defect (incompetence):
-reasons = congenital, aging -backflow of venous blood --> decrease venous return to heart --> increase intravenous pressure -increase filtration of fluids = edema -inflammation aruond affected veins triggering thrombosis -damage to vascular walls leads to internal bleeding common sites: -deep veins -low extremities, esophagus |
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What are Anastomoses?
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connecting blood vessels between:
-arterioles -venules -venules and arteries collateral circulation - provide alternate route for blood flow end arteries - do not make anastomoses |
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What is the Nerve supply of blood vessels?
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rich sympathetic supply - NAdr --> vasoconstriction of smooth muscle
Parasympathetic (except external genitalia) - Ach, NO --> causes vasodilation of smooth muscles capillaries have no nerve supply |
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What is the order of blood as it leaves the heart?
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elastic arteries --> muscular arteries --> small arteries and arterioles --> capillaries --> venules and small veins --> medium veins --> large veins
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