<Tr> <Th> FMA </Th> <Td> 70827 </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terminology (edit on Wikidata) </Td> </Tr> <P> The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart . The largest pulmonary veins are the four main pulmonary veins, two from each lung that drain into the left atrium of the heart . The pulmonary veins are part of the pulmonary circulation . </P> <P> Two main pulmonary veins emerge from each lung hilum, receiving blood from three or four bronchial veins apiece and draining into the left atrium . An inferior and superior main vein drains each lung, so there are four main veins in total . </P>

Where does the blood in the pulmonary vein come from