Cardiac Cycle

Question 1

Compare the cardiac outputs of the left and right ventricles

Answer 1

Both have the same cardiac output of around 5L/min (70ml per beat)

Question 2

What is normal cardiac output?

Answer 2

5L/min or 70ml per beat

Question 3

What do pulsations in the internal jugular vein reflect?

Answer 3

Pressure changes in the right atrium

Question 4

What is the first heart sound caused by?

Answer 4

Closing of the AV valves (bicuspid/tricuspid)

Question 5

What is the second heart sound caused by?

Answer 5

Closing of the semilunar valves (aortic/pulmonary)

Question 6

What is the third heart sound caused by?

Answer 6

Vibration of ventricle wall when filling

Question 7

What is the fourth heart sound caused by?

Answer 7

Ventricular filling during atrial systole

Question 8

What can excessive heart sounds be caused by?

Answer 8

Turbulent blood flow (e.g. blood flowing too quickly or in different directions)

Question 9

Give two causes turbulent blood flow?

Answer 9

. Stenosis (narrowing of blood vessel)

. Incompetent valve

Question 10

How does stenosis cause a heart murmur?

Answer 10

Stenosis creates a high pressure gradient so blood flow through the valves is very powerful. This means there’s a murmur when the valve ‘slams’ opens.

Question 11

How does an incompetent valve cause a heart murmur?

Answer 11

Incompetent valve allows blood to flow in different directions, so there’s a murmur when the valve should be closed