Term
| How is blood carried?(generally) |
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Definition
| Blood is a carried in a closed system of vessels that begins and ends at the heart. |
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Term
| What are the three major type of vessels? and how does each one carry blood? |
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Definition
| Veins, Arteries and capillaries. Veins are carried toward the heart, arteries carry blood away from heart and capillaries contact tissue cells and serve cellular needs |
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Term
| Tell me about the structure and functions of elastic conducting arteries? |
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Definition
| thick walled arteries near the heart , the aorta and its major branches. it contains elastin in all three tunics. it withstands and fluctuates large blood pressure. allows blood to flow smoothly throughout the body |
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Term
| tell me about the functions of muscular arteries and arterioles. |
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Definition
| muscular arteries are distal to elastic arteries. have thick tunica media with more smooth muscle and less elastic tissue. active in vaso constriction . arterioles are the smallest arteries, leads to capillary beds . control flow into capillary beds via vasodilation and constriction. |
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Term
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Definition
| capillaries are the smallest blood vessels. the walls consist of a thin tunica interna, one cell thick. allows only a single rbc to flow at a time |
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Term
| when you exercise? does the blood vessels vasodilate or vasoconstrict? |
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Definition
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Term
| what is a precapillary spinchter? |
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Definition
| cuff of smooth muscle that surrounds each true capillary. regulates blood flow into the capillary |
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Term
| how is blood flow regulated in the precapillary beds? |
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Definition
| blood flow is regulated by vasomotor nerves and local chemical conditions, so it can either bypass or flood the capillary bed |
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Term
| how is the venous system aka venules formed? what are postcapillary venules and large venules |
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Definition
| when capillary beds unite, they allow wbc to pass from bloodsteam to tissues. post capillary venules are the smallest venules composed of endothelium, large venules have one or two layers of smooth muscle (tunica media) |
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Term
| how are veins formed and what are they composed of? |
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Definition
| when venules converge and composed of three tunics, thin tunica interna and thick tunica externa consisting of collagen and elastic networks |
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Term
| which has lower pressure, veins or arteries? |
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Definition
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Term
| to return blood back to the heart, veins have special adaptations, explain them |
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Definition
| large diameter lumens which offer little resistance to flow and valves which prevent backflow of blood |
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Term
| what is vascular anastomoses? |
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Definition
| merging blood vessels, more common in veins then arteries. aetrial anastomoses provide alternate pathways (collaterel channels)for blood to reach a given body region . if one branch is blocked , the collateral channel can supply the region with adequate blood |
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Term
| Actual volume of blood flowing through a vessel, an organ, or the entire circulation in a given period is measured in? constant or not constant at rest, varies or doesnt varie |
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Definition
| ml per min, constant, varies widely through individual organs, according to immediate needs |
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Term
| most of the arteries carry oxygenated blood except? all veins carry deoxygenated blood except |
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Definition
| polmonary arteries, polmonary veins |
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Term
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Definition
| force per unit area exerted on the wall of a blood vessel its contained blood. expressed in millimeters of mercury (mm hg). The differences in BP within the vascular system provide the driving force that keeps blood moving from higher to lower pressure areas |
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Term
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Definition
| the opposition to flow, measure of friction blood encounters as it passes through vessels. the three important sources of resistance are blood viscocity, blood diameter, and blood vessel length |
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Term
| explain blood viscocity, vessel legnth |
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Definition
| blood viscoity - thickness of blood. blood vessel length, the longer the vessel, the greater the resistance encountered |
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Term
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Definition
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Term
| small diameter arterioles are the major determination of? |
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Definition
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Term
| fatty plaque acids from artherscrelosis cause |
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Definition
| turbulent , dramatically increase resistance due to turbulence |
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Term
| If blood pressure(AP) increases, blood flow _______. and if blood pressure(ap) decreases, blood flow declines |
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Definition
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Term
| if (R) resistance increases, blood flow ______ |
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Definition
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Term
| blood flow is directly __________ to the difference in blood pressure between two points in a circulation |
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Definition
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Term
| blood flow is inversely _______ to resistance |
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Definition
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Term
| what is systemic blood pressure? |
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Definition
| the pumping action of the heart genereates blood flow through the vessels along a pressure gradient, always moving from a higher to lower pressure areas. pressure results when flow is opposed by resistance |
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Term
| systemic pressure is highest in |
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Definition
| aorta and declines throughout the length of the pathway. is 0 hg in the right atrium |
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Term
| arterial blood pressure reflects two factors |
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Definition
| their elasticity, the amount of blood forced into them at any given time |
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Term
| what is systolic pressure, diastolic pressure, pulse pressure, mean arterial pressure, |
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Definition
| systolic pressure pressure exerted on arterial walls during a ventricular cycle , pulse pressure - the difference between systolic and diastolic pressure , mean arterial pressure(map)- pressure that propels the blood to the tissues. MAP = pressure |
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Term
| how much is the capillary blood pressure? and why is it desirable at this blood pressure? |
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Definition
| 20 to 40 mm hG, because high blood pressure would rupture thin walled capillaries, low bp is sufficient to force filtrate out into interstitial space and distribute nutrients gases and hormones between blood and tissues. |
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Term
| is venous blood pressure steady or unstable? |
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Definition
| steady and changes little during the cardiac cycle. the pressure gradient in the venous system is only about 20 mm Hg. |
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Term
| venous bp alone is too low to promote adequate blood return and is aided by |
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Definition
the respiratory pump - pressure changes created during breathing suck blood toward the heart by squeezing local veins.
muscular pump - contraction of skeletal muscles milk blood toward the heart |
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Term
| valves prevent _______ during venous return |
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Definition
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Term
| what are the main factors influencing blood pressure? |
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Definition
| cardiac output, periphal resistance, blood volume |
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Term
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Definition
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Term
| blood pressure varies directly with CO, PR, and BLOOD VOLUME |
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Definition
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Term
| neural controls of periphal resistance alter? maintain mAP by altering ? |
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Definition
| blood distribution to respond to specific demands. blood vessel diameter |
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Term
| neural controls operate via reflex arcs involving? |
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Definition
| baroreceptors, vasomotor centers of the medulla and vascular smooth muscle. |
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Term
| symphatetic activity causes blood pressure? |
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Definition
| vasoconstriction and rise in blood pressure if increased and blood pressure to decline is basal levels if decreased |
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Term
| vasomotor activity is modified by |
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Definition
| baroreceptors (pressure-sensitive), chemoreceptors(o2, Co2, and h plus senssitive), higher brain centers, bloodborne chemicals and hormones |
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Term
| increased blood pressure stimulates the cardioinhibitory center to |
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Definition
| increase vessel diameter, decreased heart rate , cardiac output , periphal resistance and |
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