About the Heart / Lung; Heart / Lung Center Data Profile; The aorta is the main artery that carries blood from the heart to all parts of the body except the lungs. The pulmonary artery is one of the two arteries that carry blood from the heart to the lungs. The vena cava is either of two large veins that return blood to the right atrium of the heart. The left atrium is the upper left chamber of the heart that receives blood from the pulmonary veins. The right atrium is the upper right chamber of the heart that receives blood from another part of the body and pumps it into a ventricle.