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22 Cards in this Set
- Front
- Back
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What is preferential: laminar or turbulent flow?
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Laminar flow, sometimes known as streamline flow, occurs when a fluid flows in parallel layers, with no disruption between the layers.
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What is the formula for flow?
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Q = V/T = volume/time
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With the same flow (Q), if radius increases what happens to velocity?
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Velocity decreases.
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How is turbulent flow mathematically calculated?
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Renold's number Nr = pDV/n
p = fluid density D = vessel diameter V = mean velocity n = fluid viscosity |
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What values of Rn indicate laminar and turbulent flow?
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Rn < 2000 = laminar flow
2000 < Rn < 3000 transitional Rn > 3000 = turbulent flow |
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How does fluid density, vessel diameter, mean velocity, and fluid viscosity relate to turbulence?
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Nr = pDV/n
/\ fluid density (p) -> /\ turbulence /\ diameter (D) -> /\ turbulence /\ mean velocity (V) -> /\ turbulence /\ fluid velocity -> \/ turbulence |
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What is flow?
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Q = (Pi-Po)/R
delPressure/Resistance |
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What is CO with regard to flow and pressure?
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(MAP-RAP)/Rtpr
RAP = Mean Right Atrial Pressure TPR = total peripheral resistance |
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What factor changes resistance the most?
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vessel radius because R is inversely proportional to r^4
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What is Poiseuilles' Law?
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Q = (pi)*(Pi-Po)*(r^4)/(8nl)
know how changes in left affect right |
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How do you calculate total peripheral resistance?
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TPR = (MAP-RAP)/CO
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What is the total resistance of a series arrangement of individual resistances?
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the sum of the resistances which will increase overall resistance
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What is the total resistance of a parallel arrangement of individual resistances?
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1/R = 1/R(n) + 1/R(n+1) + .....
which will decrease overall resistance |
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How does one estimate MAP?
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diastolic P + 1/3*PP
so for 150/90, diastolic P = 90, PP = 150-90 = 60 MAP = 90+60/3 = 110 |
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What causes an elevated MAP?
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/\ CO or /\ TPR
use (MAP-RAP) = CO*TPR (assume negligible RAP) |
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If brachial pressure is 150/90mmHg, then what is MAP?
What are the two possibilities to produce this pressure? |
MAP = diastolic P+1/3PP
=90+(150-90)/3 = 110 mmHg /\ CO, /\ R as TPR |
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For this pt, if normal CO is 5L/min and MAP normally is 90, then is CO or TPR the problem for him if the MAP is 110mmHg?
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Calc normal TPR
TPR = MAP/CO = 90/5 Calc pts TPR @ MAP=110mmHg TPR = MAP/CO = 110/5 So the problem is that the TPR is high. |
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If a pt has brachial P = 160/100 mmHg and the CO = 6 L/min, what is the R? What is the pts problem/why are they hypertensive? Note that for this pt, normal TPR ~ 20 mmHg/L/min.
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MAP = 100+60/3 = 120 mmHg
TPR = MAP/CO = 120/6 = 20 mmHg/L/min (normal) so the problem is /\ CO |
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If a pt has high output what are the possibilities of preload, afterload, and contractility?
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/\ preload, \/ afterload, /\ contractility
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What is the R for organ 1 and for organ 2?
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R1 = P/Q = 100/300 = 1/3
R2 = P/Q = 100/500 = 1/5 |
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MAP = 100 mmHg
Venous P = 2 mmHg Qrest = 100 ml/min Qexercise = 200 ml/min What is Rrest? Rexercise? Why is it different? |
Rrest = P/Qrest = 100/100 = 1
Rexercise = P/Qexercise = 100/200 = 0.5 vasodilation |
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What is the Fick method?
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O2 consumed/{arteriole O2 - venous O2)*100 =
VO2/([CaO2]-[CvO2])*100 = L/min Fick method in which the cardiac output is calculated as the quotient of oxygen uptake (O2) and the difference of the arterial and mixed venous oxygen content. |
