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29 Cards in this Set
- Front
- Back
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Arteries roles
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thick, muscular, elastic, lots of elastin, collagen, protein
high pressure reservoir, low capacitance, stretch when blood is ejected into them during systole; elastic recoil during diastole 120/80 mmHg, pulsatile flow |
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arterioles roles = resistance vessels
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smallest microscopic arteries, primary site of resistance in circulation
smooth muscle media; diameter changes diameter (radius) of arterioles is tightly regulated distribution of CO, site of CONTROL of blood distribution to downstream capillaries TPR (total peripheral resistance) |
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capillaries' roles = exchange vessels
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single endothelial cell layer thick, large cross sectional surface area for exchange, low velocity, site of diffusion, range from leaky (gut) to not leaky at all (brain)
RBCs and most proteins cannot cross capillary barrier |
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venules roles
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like very big capillaries, low velocity of blood flow, site where leukocytes get out of the circulation (extravasation), can be leaky (inflammation), thickness of smooth muscle varies from none to a little
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veins roles
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returns blood to heart, collagen, less elastin, thin smooth muscle media
blood reservoir (holding majority of blood volume) capacitance vessels = high compliance, add lots of blood volume w/o increasing pressure some have one way valves gravity effects blood flow in veins more than arteries due to greater compliance in veins |
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constrict arterioles-->
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BP goes up--> improve fxn of heart b/c now heart can pump more blood
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blood flow units
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mL/min
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cross sectional surface area units
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cm2
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velocity units
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cm/sec
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arteries vs. capillaries vs. venous blood flow, surface area, and velocity
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same blood flow rate, increase cross sectional area in capillaries and a little increase in veins, and decrease velocity in capillaries and a little faster in veins
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flow (Q)
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pressure gradient/resistance
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what determines resistance of blood vessels
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diameter
wider diameter (less resistance) viscosity length of vessel |
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2 ways to increase blood flow in blood vessel
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decrease resistance
increase pressure |
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how to increase pressure
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increase pumping of heart, or constrict blood vessels in periphery
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Poiseuille's law of resistance
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R = 8nl/pir^4
n = viscosity l = length double radius--> decrease resistance by 16Xs |
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increase in length of blood vessel--> _____resistance
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increase resistance
Resistance = 8nl/pir^4 |
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hematocrit increase of blood--> ______resistance
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increase viscosity--> increase resistance
Resistance = 8nl/pir^4 polycythemia--> increase anemia--> decrease resistance hemodilution--> decrease resistance |
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increasing blood pressure (MAP)-->
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increase driving pressure for blood flow to all vascular beds
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BP determined by
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TPR (arteriolar tone in vascular beds) and CO of heart
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hyperemia
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blood pressure cuff--> blood redistributes to entire body--> during ischemia those blood vessels are dilating--> release blood pressure cuff--> tons of blood can now flow thru
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hyperemia
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blood pressure cuff--> blood redistributes to entire body--> during ischemia those blood vessels are dilating--> release blood pressure cuff--> tons of blood can now flow thru
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CO equation
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Flow (Q) = pressure gradient/resistance
CO = MAP/TPR MAP = CO X TPR |
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CO equation
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Flow (Q) = pressure gradient/resistance
CO = MAP/TPR MAP = CO X TPR |
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what will happen to CO if you take a drug that activates alpha 1 adrenergic receptors throughout the body's arteries and arterioles?
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alpha 1 adrenergic receptors--> constrict arterioles--> CO decreases b/c pumping against a higher resistance
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what will happen to CO if you take a drug that activates alpha 1 adrenergic receptors throughout the body's arteries and arterioles?
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alpha 1 adrenergic receptors--> constrict arterioles--> CO decreases b/c pumping against a higher resistance
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what will happen to MAP if you take a ca2+ channel blocker that targets vascular SMC?
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relaxing SMC/arterioles--> decreases TPR--> decreases MAP
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what will happen to MAP if you take a ca2+ channel blocker that targets vascular SMC?
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relaxing SMC/arterioles--> decreases TPR--> decreases MAP
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what will happen to MAP when you exercise?
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heart rate goes up--> TPR decreases b/c dilate vessels
kidneys and stuff constrict but overall effect TPR decreases--> BP goes up a little bit but doesn't go up a lot b/c TPR goes down b/c got so much dilation |
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what will happen to MAP when you exercise?
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heart rate goes up--> TPR decreases b/c dilate vessels
kidneys and stuff constrict but overall effect TPR decreases--> BP goes up a little bit but doesn't go up a lot b/c TPR goes down b/c got so much dilation |
