What is the primary role of the ventricles during cardiac systole?

During cardiac systole, the primary role of the ventricles is to contract and pump blood into the body. This phase of the cardiac cycle is characterized by the contraction of the ventricular muscles, which generates the necessary pressure to push blood out of the heart. The right ventricle pumps deoxygenated blood into the pulmonary circulation for oxygenation, while the left ventricle pumps oxygenated blood into the systemic circulation to supply the body with the oxygen and nutrients it requires.

The other options represent different stages or aspects of the cardiac cycle but do not accurately describe the primary function of the ventricles during systole. Relaxing and filling with blood pertains to diastole, where the heart prepares for the next contraction. Checking blood pressure is not a direct function of the ventricles but rather a physiological outcome of the heart's action and the vascular system's response. Receiving blood from the atria occurs during the diastolic phase when the ventricles are filling with blood, not during systole when they actively pump.