The Cardiac Cycle

Question 1

Describe the five stages of the cardiac cycle

Answer 1

• Late diastole
• Atrial Systole
• Isovolumetric ventricular contration
• Ventricular ejection
• Isovolumetric ventricular relaxation

Question 2

What happens during late systole?

Answer 2

Both sets of chambers are relaxed and ventricles fill passively

Question 3

Whats happens during atrial systole?

Answer 3

Atrial contraction forces a small amount of blood into the ventricles

Question 4

Whats happens during isovolumetric ventricular contraction?

Answer 4

Contraction - first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semi-lunar valves

Question 5

Whats happens during ventricular ejection?

Answer 5

As ventricular pressure increases and exceeds pressure in the arteries, the semi-lunar valves open and blood is ejected

Question 6

Whats happens during isovolumetric relaxation?

Answer 6

As ventricles relax, pressure in ventricles decreases, blood flows back into the cusps of the semi-lunar valves and snaps them closed

Question 7

Stenosis of the aortic/pulmonary valves would create a murmur at what point in a normal heart phonocardiogram?

Answer 7

In-between S1 (mitral and tricuspid closure) and S2 (aortic and pulmonary closure)

Question 8

What other pathology would create a similar sound to aortic/pulmonary stenosis?

Answer 8

Mitral/tricuspid regurgitation

Question 9

Stenosis of the mitral and tricuspid valves would cause a murmur at what point in an otherwise normal phonocardiogram?

Answer 9

After S2 (aortic and pulmonary closure)

Question 10

What other pathology would create a similar sound to mitral/tricuspid stenosis?

Answer 10

Regurgitation through aortic and pulmonary valves

Question 11

What pathology would create a constant whooshing sound?

Answer 11

Septal defect