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22 Cards in this Set

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Why does pressure drop as we move through the system?
Resistance
What letters signify a heart cycle?
PQRST
How long does one heart cycle last?
800ms
How long does systole last?
300ms
How long does diastole last?
500ms
What marks the start and end of systole?
begins with contraction
stops when ejection ceases
What marks the start of diastole?
begins when ejection ceases
When does heart filling begin?
After sufficient relaxation
The pressure must lower enough to the bicuspid/tricuspid valve to open to let blood in
What forces valves open/close?
A pressure difference
When the AV valves are open, the aortic/pulmonary valves are...
closed
Starting with atrial systole, describe the heart cycle
atrial systole, ventricular systole (isovolumetric), ventricular systole (ejection phase) + atrial refill, ventricular diastole (isovolumetric), ventricular diastole (rapid filling)
atrial systole, ventricular systole (isovolumetric), ventricular systole (ejection phase) + atrial refill, ventricular diastole (isovolumetric), ventricular diastole (rapid filling)
How do you measure the pressure inside the heart?
Catheters through femoral artery
Draw a Wiggers diagram
How do you work out mABP?
(SP-DP)/3 +DP
What is the dicrotic notch/incisura?
When the blood flows back towards the ventricle, the aorta closes causing a small increase in pressure
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
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
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
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
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
How do you work out the ejection fraction?
stroke volume/EDV
should be greater than 55%
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