Blood Flow The aorta - the largest artery of the body - leads from the left ventricle and supplies the body with oxygenated blood. The pulmonary artery - leading from the right ventricle - divides into 2 branches that supply blood to the lungs. Blood that has been refreshed by the lungs is returned to the heart through the pulmonary veins, which lead to the left atrium. The venous blood from the arms, legs, torso, and head is channeled to the superior (upper) vena cava and inferior (lower) vena cava and is directed into the right atrium. The various valves of the heart ensure that blood flows through the heart in only one direction. The ventricles are divided by a thick muscular wall called the ventricular septum.
