Explain the events of the cardiac cycle, including the heart sounds.

a. during diastole the heart muscles/atria/ventricles are relaxed;
b. blood enters the atria;
c. during atrial systole the atria contract and blood moves into the ventricles;
d. pressure (in ventricles) causes bicuspid/tricuspid/AV valves to close;
e. (this) closing of valves causes first heart sound;
f. during ventricular systole the ventricles contract causing blood to flow to aorta/pulmonary artery/arteries/out of heart;
g. semilunar valves close so blood does not return to the ventricles;
h. this causes the second heart sound;
i. blood leaving atria/ventricles during contraction is caused by increased pressure which reduces volume;

Most candidates demonstrated a sound understanding of this topic and scored high for this question, but many did not distinguish between the events of the cardiac cycle and the mechanisms that control the heartbeat, including everything in their answer and perhaps losing precious time. Many answers incorporated the same unnecessary details, probably learned from the same manual. Sometimes the weaker candidates only described the events on one side of the heart and did not refer to pressure, systole or diastole. There was also sometimes some confusion about the opening and closing of the valves.