The cardiac cycle

Question 1

Define Venous Return -

Answer 1

Blood returning to the heart from the systemic circulation and pulmonary circulation passes through the AV valves under its own pressure

Question 2

Define Isovolumetric contraction -

Answer 2

Ventricles contract, but pressure is not yet enough to open semilunar valves, therefore ventricular volume remains constant

Question 3

Define Ventricular Ejection -

Answer 3

Exit of blood from the ventricles

Question 4

Define Isovolumetric relaxation -

Answer 4

Ventricles relax, but still too much pressure to allow AV valves to open and not enough pressure to maintain semi-lunar valves open. Therefore all valves are shut and there is no change in blood volume in ventricles

Question 5

Define Ventricular filling -

Answer 5

Blood enters ventricles from atria

Question 6

What is aortic pressure?

Answer 6

Aortic pressure is used as a measure of blood pressure

Question 7

What are the stages of aortic pressure?

Answer 7

1st stage – Diastole occurs - aortic valve is closed and pressure decreases as blood leaves aorta
2nd stage – Aortic valve opens and pressure increases as blood enters aorta
3rd stage – pressure decreases as blood leaves aorta
and Dicrotic notch occurs caused by shutting of aortic valve.

Question 8

What is the minimum and maximum aortic pressure reached?

Answer 8

minimum - diastolic

maximum - systolic

Question 9

Definitions of DP, SP & MAP -

Answer 9

Lowest pressure in the aorta = Diastolic pressure (DP)
Highest pressure in the aorta = Systolic pressure (SP)
Average aortic pressure = Mean arterial pressure (MAP)

Question 10

How do you find out pulse pressure?

Answer 10

Pulse pressure = Systolic pressure – Diastolic pressure

Question 11

How do you find out MAP?

Answer 11

MAP = Diastolic pressure + (Pulse pressure/3)

Question 12

What is ESV and EDV?

Answer 12

Volume of blood in ventricle at end of diastole is EDV

Volume of blood in ventricle at end of systole is ESV

Question 13

How do you calculate stroke volume?

Answer 13

(SV) = EDV-ESV

Question 14

What is the Ejection fraction and how do you calculate this?

Answer 14

Ejection fraction (EF) - ratio of volume ejected in one beat to volume immediately prior to ejection
EF = SV/EDV

Question 15

What causes Coronary artery disease

Answer 15

Due to accumulation of plaques in coronary arteries
Plaques restrict blood flow to the myocardium
Can lead to chest pain (angina pectoris) and heart attack

Question 16

What are some risk factors that can cause coronary artery disease

Answer 16

Genetic predisposition
High blood cholesterol 
High blood pressure
Diabetes 
Obesity
Sedentary lifestyle
Cigarette smoking

Question 17

What causes the heart sounds?

Answer 17

the turbulent rush of blood through valves as they CLOSE

Question 18

what causes 1st lub sound

Answer 18

1st lub sound is caused by AV valves closing

Question 19

what causes 2nd lub sound

Answer 19

2nd lub sounds is caused by SL valves closing