What happens during ventricular systole in the cardiac cycle?

During ventricular systole in the cardiac cycle, the ventricles experience contraction, generating pressure that forces blood out of the heart. This phase is critical for maintaining circulation as it pumps oxygen-rich blood from the left ventricle into the aorta, delivering it throughout the body, while the right ventricle pumps deoxygenated blood into the pulmonary artery, directing it to the lungs for oxygenation.

This contraction is initiated by the electrical impulses from the sinoatrial (SA) node traveling through the atrioventricular (AV) node and down the Purkinje fibers, resulting in a coordinated contraction of the ventricular muscle. The high pressure generated during this phase is essential for overcoming the pressure in the aorta and pulmonary arteries, enabling effective circulation.

Other options reflect different phases or aspects of the cardiac cycle that do not occur during ventricular systole: the filling of the ventricles and contraction of the atria happen during diastole, while the resting state of the heart occurs when it is not actively pumping, which is also not characteristic of ventricular systole.