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18 Cards in this Set
- Front
- Back
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What is the equation for the velocity of blood flow?
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v=Q
___ A v= velocity of blood flow(cm/s), Q=blood flow(mL/s), A= cross sectional area |
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What famous law is the equation for blood flow analagous to?
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Ohm's law: I=V/R
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What factors change the resistance of the vasculature system proportionally?
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Viscosity and length of the vessel.
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In what physiological states does viscosity exist?
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Polycythemia
Hyperproteinemia Hereditary spherocytosis |
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What happens to the resistance if the radius of the blood vessel is reduced by 50%?
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Increased by a factor of 16(R is proportional to [1/r4th].
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Where does the largest decrease in vascular pressure occur?
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Across the arterioles, which is the site of greatest resistance in the system.
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What is the equation for capacitance?
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C=V
____ P C= capacitance(ml/mm Hg), V= volume(mL), P= pressure(mm Hg) |
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Which has more capacitance, an artery or a vein? WHY?
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Capacitance is inversely related to elastance. Since aretries have more elastic tissue compared to veins, they have less capacitance.
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When is the systolic pressure measured?
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After the heart contracts
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When is diastolic pressure measured?
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After the the heart relaxes.
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How can you calculate the pulse pressure?
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Pulse pressure= systolic- diastolic
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What is the major determinant of pulse pressure?
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Stroke volume(SV)
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What happens to the pulse pressure when the capacitance decreases?
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Increases
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What is the mean arterial pressure(MAP)?
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Average arterial pressure with respect to time.
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How can you determine MAP?
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MAP= CO X TPR
MAP = 1/3 systolic + 2/3 diastolic TPR= total peripheral resistance |
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Which is lower, venous pressure or atrial?
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Atrial pressure
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How can the left atrial(LA) pressure be estimated?
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Pulmonary capillary wedge pressure(PCWP).
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What is used to measure LA pressure?
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Swan-Ganz catheter.
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