During the cardiac cycle,
A) the right atrium and the right ventricle contract simultaneously.
B) the two atria relax while the two ventricles contract.
C) the left atrium contracts before the right atrium.
D) all four chambers of the heart contract at the same time.
E) all four chambers of the heart are in systole at the same time.

Question

Quizplus · Accepted Answer

During the cardiac cycle, the heart operates in two main phases: systole and diastole. During systole, the ventricles contract to pump blood out of the heart, while the atria are relaxed and filling with blood. This is accurately described in option B, where the two atria relax while the two ventricles contract.

During the Cardiac Cycle