Heart and lungs. Historical artwork of the heart (red) and lungs (orange, left and right) seen from behind. Dissection hooks have been used to draw back the lung tissue. Air is drawn into the lungs through the trachea (orange, upper centre) that passes down the throat from the mouth. The trachea branches into two bronchi, one for each lung. The heart pumps blood round the body and to the lungs. Blood from the body arrives through the vena cava veins (one at lower right, red), is pumped to the lungs through the pulmonary arteries (orange, partly seen behind the bronchi), returns through the pulmonary veins (red, centre left and centre right) and is pumped round the body via the aorta (large artery, orange, arching behind trachea). The lungs oxygenate the blood.