The ventricles of the heart function to pump blood to the entire body.Papillary muscles in the ventricle walls control the opening and closing of the tricuspid valve and mitral valve.Blood returning to the heart from the lungs enters the left atrium and passes through the mitral valve to the left ventricle.During the diastole phase of the cardiac cycle, the atria and ventricles are relaxed and the heart fills with blood.During the systole phase, the ventricles contract pumping blood to the major arteries (pulmonary and aorta).Right ventricle: Receives blood from the right atrium and pumps it to the main pulmonary artery.The pulmonary artery extends from the right ventricle and branches into the left and right pulmonary arteries.