3 Cardiac Cycle

Question 1

What is arterial blood pressure equal to?

Answer 1

ABP = SV x HR x TPR

Question 2

What is energy of the blood equal to?

Answer 2

pressure x momentum

Question 3

What are the 3 stages of Ventricular diastole?

Answer 3

isovolumetric relaxation
rapid/passive filling
atrial systole, ventricular filling

Question 4

what are the 2 stages to Ventricular systole?

Answer 4

isovolumetric contraction

ejection

Question 5

What is the P wave stimulating?

Answer 5

atrial contraction

Question 6

What is the QRS wave stimulating?

Answer 6

ventricular contraction

Question 7

What is the T wave stimulating?

Answer 7

ventricular repolarisation, and hence relaxation

Question 8

What are the 2 heart sounds from?

Answer 8

lub - A-v valve closing

dub - aortic and pulmonary valves closing

Question 9

How do we calculate stroke volume?

Answer 9

the difference between endiastolic and ensystolic volumes

Question 10

What happens in the passive filling phase of ventricular diastole?

Answer 10

The atrial pressure exceeds that of the ventricles, blood pours into ventricles htrough open mitral valve, increasing pressure in the ventricle as the aortic valve is closed

Question 11

What is aortic pressure like in the passive filling stage of ventricular diastole?

Answer 11

it is far higher than ventricular, so the aortic valve is closed

it is decreasing as the blood is moved off towards peripheral tissues

Question 12

What is happening in the isovolumetric contraction phase of ventricular systole?

Answer 12

ventricular depolarisation (QRS)
P(atrial) < P(ventricular) < P(aortic)
A-V valve closes
No change in LV volume
small peak in atrial pressure as A-V valve pushes into atria

Question 13

What is the purpose of isovolumetric contraction?

Answer 13

allows the ventricular pressure to rise above the aortic pressure, before opening the aortic valve

Question 14

What happens to atrial pressure over ventricular systole?

Answer 14

decreases a bit, after push into atria during isovolumetric contaction

then increases gradually as it fills again

Question 15

What is the relationship between ventricular and aortic pressure in ejection?

Answer 15

the valve is open, so any change will occur in both areas

Ultimately, the aortic pressure will exceed the ventricular pressure, the momentum of the blood will combat this

Question 16

What causes ejection to slow?

Answer 16

relaxation of the ventricle stimulated by the T wave

Question 17

What happens after the T wave?

Answer 17

ventricle relaxes
aortic valve will have to close as momentum is not enough to push blood into aorta, so this prevents backflow

isometric relaxation

Question 18

What is the function of isometric relaxation?

Answer 18

to reduce intraventricular pressure down to below atrial pressure so it can fill again

Question 19

What happens to the P wave during an increased heart rate?

Answer 19

the P wave moves further to the left, decreasing the distance between the P and the T wave, reducing passive filling time in ventricular diastole?

Question 20

How can lost time in passive filling ventricular diastole be compensated for?

Answer 20

greater force of atrial contraction stimulated by the P wave can compensate

Question 21

What should the relationship between right cardiac and left cardiac flow be?

Answer 21

equal, ideally

Question 22

Why is ride side heart pressure lower than left?

Answer 22

pulmonary vascular resistance is low because the vessels are wider and shorter

Question 23

when is aortic diastolic pressure measured?

Answer 23

just before the aortic valve open, the lowest aortic pressure reached