The Cardiac Cycle

Question 1

What are the stages in the cardiac cycle?

Answer 1

1. Atrial and ventricular diastole
2. Atrial systole
3. Isovolumic contraction
4. Ventricular ejection
5. Isovolumic ventricular relaxation

Question 2

Describe atrial and ventricular diastole

Answer 2

Atria fills with blood from veins

Ventricles relax, AV valves open and blood flows in from atria

Question 3

Describe atrial systole

Answer 3

Force a small amount of additional blood into the V

Small amount of blood pushed back into vein - JVP

Question 4

Describe isovulmic ventricular contraction

Answer 4

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

Question 5

Describe ventricular ejection

Answer 5

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

Question 6

Describe isovolumic ventricular relaxation

Answer 6

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

Question 7

What is used instead of SV to assess the healthiness of someone’s heart?

Answer 7

Ejection fraction = SV/EDV

Question 8

What causes the first heart sounds (S1)?

Answer 8

Closing of mitral and tricuspid valve during systole

Question 9

What causes the second heart sound (S2)?

Answer 9

Closing of the semilunar valves during diastole

Question 10

What can cause a systolic murmur?

Answer 10

Stenosis of semilunar valves

Regurgitation of mitral or tricuspid valves

Question 11

What can cause a diastolic murmur?

Answer 11

Stenosis of mitral or triscuspid valves

Regurgitation of semilunar valves

Question 12

What can cause a systolic and diastolic murmur?

Answer 12

Septal defect

Or calcification of valves causing stenosis and regurgitation