Pulmonary vein Pulmonary vein 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. 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. At the root of the lung, the right superior
Biofluid dynamics oxygen. The red blood cells and the hemoglobin present in the blood, which is the main carrier of oxygen in the blood are responsible for this exchange of gases before they are carried to the left ventricle of the heart. The systemic circulation is responsible for taking the oxygenated blood to various organs and tissues via the arterial tree before taking the deoxygenated blood to the right ventricle using the venous system (a network of veins). Arteries carry the oxygenated blood while the veins carry the deoxygenated blood. The fluids associated with the human body include air, oxygen, carbon dioxide,