False-colour scanning electron micrograph (SEM) of the mucous-secreting, epithelial wall of bile duct (biliary tract). Bile is a thick alkaline fluid that is produced by liver & stored in the gall bladder which drains into the duodenum via the common bile duct. Bile salts assist in emulsifying fats in the duodenum prior to being digested by pancreatic enzymes to form fatty acids & glycerol. Bile also helps stimulate peristalsis in the duodenum, the wave-like contraction of the walls of the intestines that propels their contents forwards. Magnification: X 10 at 35mm size.