What is the function of the right and left pulmonary vein?
All veins carry blood to the heart, and pulmonary veins are specifically veins that carry oxygenated blood (oxygenated in the lungs) from the lungs to the heart. In other words, the left pulmonary vein carries oxygenated blood from the left lung to the heart, and the right pulmonary vein carries oxygenated blood from the right lung to the heart.