Illustration of the blood vessels of the gallbladder. The cystic artery (red) supplies the gallbladder with oxygenated blood and the cystic vein (blue) drains unoxygenated blood. The gallbladder stores and concentrates bile produced by the liver and secretes it, via the cystic duct (yellow), into the small intestines where it helps the body to digest fat. From Traite dAnatomie Humaine, Vol. 4 (1905) by French anatomist Leo Testut (1849-1925).