Where is the blood carried in first loop of circulatory system?

The first circulatory system, also called the pulmonary circulation, carries deoxygenated blood from the heart to the lungs and back to the heart. The right atrium receives deoxygenated blood from the body and pumps it into the right ventricle, which then contracts and pumps the blood into the pulmonary artery, the primary blood vessel that carries blood from the heart to the lungs. The pulmonary artery divides into two branches, one going to each lung. The pulmonary veins then carry oxygenated blood from the lungs to the heart.