Synthesized in the liver, bile is an essential fluid for digestion.

Bile consists primarily of water, cholesterol, lecithin, inorganic salts, bile salts and bile pigments. The bile salts are comprised of cholesterol derived acids which are synthesized in the liver. The bile pigments are hemoglobin metabolites. The two major bile pigments are biliverdin and bilirubin.

After being manufactured in the liver, bile is transported through the hepatic duct to the gall bladder, where it is stored until needed. While sitting in the the gall bladder, the bile is concentrated as the inorganic salts are actively transported out. This creates an osmotic imbalance, inducing water to flow out of the bile.

Bile has three major functions.
  • First, because of its strong alkalinity, it is important in the final stages of digestion to neutralize the strong gastric acids.
  • Second, the bile salts are able to disperse fat and lipid soluble vitamins for easy digestion and transport through the blood. Because bile salts are amphipathic, they can bind the non-water soluble material while staying in solution themselves.
  • Third, the bile carries some of the water insoluble waste substances that are removed from the bloodstream by the liver such as hemoglobin pigments, cholesterol, steroids and various drugs. These are then expelled along with the remaining digestive waste.

To add to Halcyon&on's excellent writeup above:

The gallbladder contracts, releasing bile into the bile duct when stimulated by the hormone cholecystokinin. Cholecystokinin is released by cells in the duodenum, with food and especially with fatty food. This bile travels down the bile duct into the head of the pancreas and joins with the pancreatic duct before emptying into the second part of the duodenum at the ampulla of Vater (a.k.a. the sphincter of Oddi).

The presence of a greenish tinge in vomitus is a good indication that the vomitus has come from below the level of the duodenum (i.e. past the stomach).

Any obstruction to the passage of bile can result in obstructive jaundice as the bilirubin that is normally excreted through the bile ends up building up in the body.

Bile (?), n. [L. bilis: cf. F. bile.]

1. Physiol.

A yellow, or greenish, viscid fluid, usually alkaline in reaction, secreted by the liver. It passes into the intestines, where it aids in the digestive process. Its characteristic constituents are the bile salts, and coloring matters.


Bitterness of feeling; choler; anger; ill humor; as, to stir one's bile.


⇒ The ancients considered the bile to be the "humor" which caused irascibility.


© Webster 1913.

Bile, n. [OE. byle, bule, bele, AS. ble, bl; skin to D. buil, G. beule, and Goth. ufbauljan to puff up. Cf. Boil a tumor, Bulge.]

A boil.

[Obs. or Archaic]


© Webster 1913.

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