Which event typically occurs at the start of a cardiac cycle?
A) Ventricular blood pressure drops until reverse blood flow pushes the cusps of the semilunar valves together.
B) Atrial contraction forces a small amount of blood into the relaxed ventricles.
C) The semilunar valves open and blood is ejected.
D) Ventricular contraction pushes the atrioventricular valves closed.
E) The atrioventricular valves opens and the ventricles fill passively.
Ans: B) Atrial contraction forces a small amount of blood into the relaxed ventricles.
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