Question

Categorize following statements between either False or True

a) Av and semilunar valves are never open at the same time during cardiac cycle
b) When atria contract, the blood is forced into ventricles through open AV valves
c) AV and semilunar valves are never closed at the same time during cardiac cycle
d) Cardiac cycle begins with early ventricular systole
e) The term "cardiac cycle" has the same meaning as "cardiac output"

Answer 1

a) False, b) True, c) False, d) False, e) False.

Step-by-step explanation:

a) False: Av and semilunar valves are open at the same time during the cardiac cycle. In Figure 19.13a, the two atrioventricular valves are open and the two semilunar valves are closed, occurring when both atria and ventricles are relaxed.

b) True: When atria contract, the blood is forced into ventricles through open AV valves. This can be seen from Figure 19.13a, where the atrioventricular valves are open and blood is flowing from the atria into the ventricles.

c) False: AV and semilunar valves are closed at the same time during the cardiac cycle. The atrioventricular valves are closed while the two semilunar valves are open, occurring when the ventricles contract to eject blood into the pulmonary trunk and aorta.

d) False: The cardiac cycle begins with early ventricular systole. At the beginning of the cardiac cycle, both the atria and ventricles are relaxed (diastole), as mentioned in the reference.

e) False: The term 'cardiac cycle' does not have the same meaning as 'cardiac output.' Cardiac cycle refers to the sequence of events that occur in the heart during one heartbeat, while cardiac output refers to the volume of blood pumped by the heart per minute.