Parasympathetic (vagal) stimulation results in contraction of the gallbladder and relaxation of the sphincter of Oddi as well as increased bile formation.
The presence of protein and fat in the duodenum stimulates the release of cholecystokinin (CCK).
CCK is the most powerful signal for gallbladder contraction and also mediates relaxation of the sphincter of Oddi
Metabolic processing of nutrients after their absorption
Storing glycogen, fats, iron, many vitamins
Bile salts, along with cholesterol and lecithin play an important role in facilitation
fat absorption via micelles
Detoxification and elimination body wastes, drugs and other foreign substances
Synthesizing of plasma proteins
Secretion of bile
contains: bile salts (derivatives of cholesterol and aid fat digestion through their detergent action (emulsification)), cholesterol, lecithin and bilirubin (all derived from hepatocyte activity) in an aqueous alkaline fluid (added by the duct cells).
Any substance that increases bile secretion by the liver is called a choleretic.
The most potent choleretic is bile salts themselves
Secretin is released in response to low pH in the duodenum and stimulates an aqueous alkaline portion of bile
secretion by the hepatic duct cells.
evokes bicarbonate secretion from the pancreatic ducts and biliary ducts, thereby
neutralizing gastric acid in the duodenal lumen
Bilirubin - Yellow pigment that gives bile yellow color
Does not play a role in digestion
Metabolized by intestinal bacteria to urobilinogen (colorless)
80% of the urobilinogen is metabolized by bacteria and colors feces with stercobilin (brown).
Waste product excreted with the bile
Jaundice - bilirubin is formed more rapidly than it can be excreted,
it accumulates in the body
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