What occurs when the ventricles are in the systole phase?

During the systole phase of the cardiac cycle, the ventricles contract, which is fundamental to the heart's pumping function. This contraction forces the blood out of the ventricles into the pulmonary artery and the aorta. Specifically, the right ventricle pumps deoxygenated blood to the lungs through the pulmonary artery for oxygenation, while the left ventricle pumps oxygenated blood to the rest of the body through the aorta. This critical action of pumping blood out of the chambers is essential for maintaining adequate circulation and delivering oxygen and nutrients to the tissues.

The other options do not accurately describe what occurs during systole. For example, during diastole, the ventricles are in the filling phase and receive blood from the atria, rather than releasing blood. Thus, the focus during systole is clearly on the contraction of the ventricles and the expulsion of blood, making the correct understanding of this phase crucial for understanding cardiac physiology.