The Cardiac Cycle

Question 1

Describe the cardiac cycle

Answer 1

1. Late diastole: complete relaxation
2. Atrial systole
3. Start of ventricular contraction: mitral valve closes, pulmonary and aortic valves open
4. End of ventricular contraction: AV valves open
5. Ventricular ejection: semi-lunar valves open
6. Ventricular relaxation: semi-lunar valves close (S2), mitral valve opens, pulmonary and aortic valves close

Question 2

Name the atrioventricular valves

Answer 2

Tricuspid valve on the right side and mitral (bicuspid) valve on the left side.

Question 3

What is end systolic volume (ESV)?

Answer 3

Filled volume of blood remaining in the ventricle after ejection.

Question 4

What is end diastolic volume (EDV)?

Answer 4

Filled volume of blood remaining in the ventricle prior to contraction.

Question 5

What is stroke volume (SV)?

Answer 5

The volume of blood pumped from the left ventricle per beat.
SV = EDV - ESV

Question 6

What is systolic pressure?

Answer 6

Pressure in the arteries during contraction (120mmHg).

Question 7

What is diastolic pressure?

Answer 7

Pressure in the arteries during relaxation (80mmHg).

Question 8

What is pulse pressure?

Answer 8

The difference between the systolic and diastolic pressures (30-50mmHg).

Question 9

What is ejection fraction?

Answer 9

Percentage of blood ejected from the left ventricle per beat.
EF = SV/EDV

Question 10

What is a dicrotic notch on a blood pressure diagram of the cardiac cycle?

Answer 10

A secondary upstroke in the descending part of a pulse tracing, caused by the transient increase in aortic pressure after closure of the aortic valve.

Question 11

What abnormality causes sound throughout the cardiac cycle?

Answer 11

Septal defect