coloured compounds – breakdown products of the blood pigment *haemoglobin – that are excreted in *bile. The two most important bile pigments are bilirubin, which is orange or yellow, and its oxidized form biliverdin, which is green. Mixed with the intestinal contents, they give the brown colour to the faeces (see urobilinogen).
A thick, bitter, greenish-brown ?uid, secreted by the liver and stored in the gall-bladder (see LIVER). Consisting of water, mucus, bile pigments including BILIRUBIN, and various salts, it is discharged through the bile ducts into the intestine a few centimetres below the stomach. This discharge is increased shortly after eating, and again a few hours later. It helps in the digestion and absorption of food, particularly fats, and is itself reabsorbed, passing back through the blood of the liver. In JAUNDICE, obstruction of the bile ducts prevents discharge, leading to a build-up of bile in the blood and deposition in the tissues. The skin becomes greenish-yellow, while the stools become grey or white and the urine dark. Vomiting of bile is a sign of intestinal obstruction, but may occur in any case of persistent retching or vomiting, and should be fully investigated.... bile
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