Circulatory system, historical artwork. Blood is pumped away from the heart (upper centre) in arteries, and returns to the heart in veins. Here, the arteries carrying oxygenated blood are red and the veins carrying deoxygenated blood are blue. The exceptions to this rule are the blue pulmonary arteries that carry deoxygenated blood from the heart to the lungs (left and right of the heart) and the red pulmonary veins that carry oxygenated blood from the lungs to the heart. Other organs shown are the stomach (centre right), liver (centre left), kidneys (below stomach and lower left) and intestines (lower centre). Artwork from La Construction du Corps Humain (Construction of the Human Body), Munich, 1880.