Lecture 12: Cardiac Cycle

Question 1

what is diastole

Answer 1

period of relaxation and filling of the heart chambers

Question 1

what is systole

Answer 1

contraction and ejection of blood
two phases
1. isovolumetric (volume same, pressure increases)
2. isotonic (volume decreases, pressure unchanged)

Question 2

what is afterload

Answer 2

the force that resists ejection of blood (prevents seminlunar valves from opening)

Question 3

what phases of the cardiac cycle make up systole

Answer 3

isovolumetric ventricular contraction
rapid ventricular ejection
reduced ventricular ejection

Question 4

what phases of the cardiac cycle make up diastole

Answer 4

isovolumetric ventricular relaxation
rapid ventricular filling
reduced ventricular filling

Question 5

how is the direction of blood flow through the heart established

Answer 5

valves (AV and semilunar)

Question 6

is the opening and closing of valves passive or active

Answer 6

passive, occurs due to the difference in blood pressure across valves

Question 7

what happens at the AV valves during diastole

Answer 7

BP in atria > ventricle, AV valves kept open, ventricle is filling

Question 8

what happens at AV valves during systole

Answer 8

BP in ventricle > atrium, AV valve is closed, prevents backflow

LUB