Cardiac cycle

Question 1

What happens during late diastole ?

Answer 1

Both sets of chambers are relaxed and ventricles fill passively

Question 2

What happens during atrial systole ?

Answer 2

Atrial contraction forces a small amount of additional blood into ventricles

Question 3

What happens during isovolumic ventricular contraction ?

Answer 3

First phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves

Question 4

What happens during ventricular ejection ?

Answer 4

As ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected

Question 5

What happens during isovolumic ventricular relaxation ?

Answer 5

As ventricles relax, pressure in ventricles falls, blood flows back into cusps of semilunar valves and snaps them closed

Question 6

What is the small rise in pressure between the aortic valve closing and the mitral valve opening because of ?

Answer 6

It is known as the dicrotic notch, small bounce in pressure due to the aortic valve closing

Question 7

What is the mean arterial pressure ?

Answer 7

Roughly diastolic plus one third of the pulse pressure

Question 8

What is happening in the atrium during ejection phase ?

Answer 8

Filling with blood from the lungs (pulmonary vein)

Question 9

What are average values for EDV and ESV ?

Answer 9

EDV = 140 ml

ESV = 60 ml

Stroke volume is therefore about 80 ml

Question 10

What is meant by ejection fraction ?

Answer 10

Stroke volume divided by EDV, usually around 2/3, unhealthy if less than that

Question 11

How do heart sounds occur ?

Answer 11

Due to turbulence in the blood

Question 12

What is the 1st heart sound due to ?

Answer 12

Closure of the mitral and tricuspid valves (AV valves)

Question 13

What is the second heart sound due to ?

Answer 13

Closure of aortic and pulmonary valves (SL valves)

Question 14

What are abnormal heart sounds ?

Answer 14

Murmurs

Question 15

What happens to the valves during systole ?

Answer 15

The mitral and tricuspid valve are shut and aortic and pulmonary valve are open

Question 16

What happens to the valves during diastole ?

Answer 16

The pulmonary and aortic valve are shut and mitral and tricuspid valve are open

Question 17

What can cause a systolic murmur ?

Answer 17

Stenosis of aortic and pulmonary valves or reguritation through mitral and tricuspid valves

Question 18

What can cause a diastolic murmur ?

Answer 18

Stenosis of mitral and tricuspid valves or regurgitation through aortic and pulmonary valves

Question 19

What can cause a continous murmur ?

Answer 19

Septal defect