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22 Cards in this Set
- Front
- Back
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Why does pressure drop as we move through the system?
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Resistance
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What letters signify a heart cycle?
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PQRST
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How long does one heart cycle last?
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800ms
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How long does systole last?
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300ms
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How long does diastole last?
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500ms
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What marks the start and end of systole?
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begins with contraction
stops when ejection ceases |
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What marks the start of diastole?
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begins when ejection ceases
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When does heart filling begin?
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After sufficient relaxation
The pressure must lower enough to the bicuspid/tricuspid valve to open to let blood in |
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What forces valves open/close?
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A pressure difference
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When the AV valves are open, the aortic/pulmonary valves are...
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closed
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Starting with atrial systole, describe the heart cycle
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atrial systole, ventricular systole (isovolumetric), ventricular systole (ejection phase) + atrial refill, ventricular diastole (isovolumetric), ventricular diastole (rapid filling)
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How do you measure the pressure inside the heart?
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Catheters through femoral artery
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Draw a Wiggers diagram
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How do you work out mABP?
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(SP-DP)/3 +DP
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What is the dicrotic notch/incisura?
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When the blood flows back towards the ventricle, the aorta closes causing a small increase in pressure
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Atrial systole:
Which valves are open/close What is the difference in pressure between the atria and the ventricle? Which ECG waves? What happens to ventricular volume? EDV |
open: aortic/pulmonary
closed: AV high in atrium P 10% increase 120ml |
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Isovolumetric contraction:
Which valves are open/close at the end of this phase? Which ECG wave? What happens to ventricular pressure? What happens to the valves as a result of this pressure? As a result of this AV valve closing... What happens to the volume of blood in the ventricle? |
Everything is closed
QRS Increases rapidly AV valves close because ventricular pressure is higher in ventricles than atria The first heart sound is closed Stays the same |
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Rapid ejection:
At the start of this phase, which valves are opened/closed? What happens to the pressures? What happens because of this? And then... At the end of this phase, which valves are open/closed |
Both closed
Ventricular pressure exceed aortic pressure Aortic/Pulmonary valves open Ejection AV closed, Pulmonary/Aortic open |
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Reduced ejection
At the start of the phase, which valves are open/closed? Which ECG wave? What happens to ventricular pressure? What happens to the aortic valve? |
Pulmonary/aorta valve are open, AV closed
T Decreases below aortic pressure Remains open because blood flow still has energy to maintain it open |
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Isovolumetric relaxation:
At the start of the phase, what valves are open and closed? What marks the second heart sound? What is the ESV? What happens to ventricular pressure? What happens to the volume of blood in the ventricle? |
AV closed, Aortic/Pulmonary open
When the aortic valve closes 50ml Falls rapidly Does not change |
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How do you work out the ejection fraction?
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stroke volume/EDV
should be greater than 55% |
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Filing:
At the start of this phase, which valves are open/closed? What happens to the pressures? What happens as a result of this? What happens due to this? |
everything closed
Pressure in atria exceed ventricular pressure Causes AV to open Rapid filling and then reduced filling |
