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20 Cards in this Set
- Front
- Back
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what are the pressures in the atria? right ventricle? left ventricle?
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- atria: 5mmHg
- RV: 25/0mHg - LV: 120/0mmHg |
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what is the formula for CO?
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- CO = HR x SV
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how do you measure CO? what is it excluding?
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- ultrasound doppler measures cross sectional area of aorta & velocity of aorta
- A (cm^2) x V (cm/min) = Q (cm^3/min) - technique measures CO minus coronary flow |
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what is the formula for the velocity of blood? what is the constant variable?
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- velocity = Q (cm^3/min) / A (cm^2)
- flow is constant |
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what happens to the velocity of blood as the area increases or decreases?
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- as area increases velocity gets smaller (capillary beds)
- as area decreases (aorta) flow increases - this is because flow is constant? |
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what is the relationship between pressure & flow?
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- P = QR
- P = pressure drop |
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what is the biggest variable that effects the resistance of a vessel?
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- the radius (b/c r^4)
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what happens to the resistance if vessel diameter decreases?
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- reistance increases by a factor of (^4)
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what is the formula for the MAP?
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- (sytolic P - diastolic P) / 3 + diastolic P
- aka pulse pressure/3 + diastolic P |
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what is the formula for the pressure drop between aorta & venous circulation?
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- Pao - Pvc = CO x TPR
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where does the largest drop in the circulation occur?
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- arterioles b/c of high resistance
- P = QR |
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what are the a, c & v atrial waves?
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- a: atrial systole
- c: backward pressure of mitral valve - v: pressure rise due to atrial filling |
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what is the x descent?
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- during ventricular contraction the pressure in the atria decreases
- this is before the filling pressures (v wave) |
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what is the y descent?
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- blood rapidly passes through mitral valve into ventricle
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when is ventricular contraction isovolumentric?
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- until it exceedes the pressures in the aorta & opens the aortic valve
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what is S1?
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- during ventricular systole, hearing turbulance of blood when ventricle is contracting
- lub |
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what is S2?
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- when aortic valve closes you hear the turbulance, at the beginning of ventricular diastole
- sharper & higher pitched than S1 - dub |
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what is the ejection fraction?
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- only about 50% of the EDV is ejected
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what is the inscisura/dichrotic notch?
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- recoil of previously stretch aorta causes secondary rise in pressure
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how does ejection speed change throughout the contraction?
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- it is initially rapid then slows as the contraction is completed
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