Blood  |  Heart → Aorta → Arteries → Arterioles → Capillaries → Venules → Veins → Vena cava → Heart → Pulmonary arteries → Lungs → Pulmonary vein Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Diagram of the human circulatory system. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... The heart and lungs, from an older edition of Grays Anatomy. ... The largest artery in the human body, the aorta originates from the left ventricle of the heart and brings oxygenated blood to all parts of the body in the systemic circulation. ... Section of an artery For other uses, see Artery (disambiguation). ... An arteriole is a blood vessel that extends and branches out from an artery and leads to capillaries. ... The word capillary is used to describe any very narrow tube or channel through which a fluid can pass. ... In the circulatory system, a vein is a blood vessel that carries blood toward the heart. ... The brachiocephalic veins, superior vena cava, inferior vena cava, azygos vein and their tributaries The superior and inferior venae cavae are the veins that return the blood from the body into the heart. ... The heart and lungs, from an older edition of Grays Anatomy. ... The pulmonary arteries carry blood from the heart to the lungs. ... The human lungs are the human organs of respiration. ... The pulmonary veins carry oxygen rich blood from the lungs to the left atrium of the heart. ...