Right pulmonary veins
Veins are the blood vessels that carry blood to the heart. Pulmonary veins are responsible for carrying oxygenated blood from the lungs back to the left atrium of the heart. This differentiates the pulmonary veins from other veins in the body, which are used to carry deoxygenated blood from the rest of the body back to the heart. Humans have four pulmonary veins in total, two from each lung. There are two right pulmonary veins, known as the right superior and right inferior veins. These carry blood from the right lung. Each pulmonary vein is linked to a network of capillaries (small blood vessels) in the alveoli of each lung. Alveoli are tiny air sacs within the lungs where oxygen and carbon dioxide are exchanged. These capillaries eventually join together to form a single blood vessel from each lobe of the lung. The right lung contains three lobes, while the left lung is slightly small and contains only two lobes. Initially there are three vessels for the right lung, but the veins from the middle and upper lobes of the right lung tend to fuse together to form two right pulmonary veins. The right pulmonary veins pass behind the right atrium and another large blood vessel known as the superior vena cava.