Short notes on the structure and functions of gall bladder

This is a pear shaped sac having approximately a capacity of sixty ml and is attached to the under surface of the right lobe of the liver. Structurally the gall bladder consists of three coats. These are an outer peritoneal coat, a middle muscular coat and an inner coat of mucous membrane. The neck of the gall bladder gives out the cystic duct which joins with the common hepatic duct.

The gall bladder mainly acts as a reservoir of the bile. The bile juice after it leaves the liver through the common hepatic duct moves up the cystic duct into the gall bladder. The mucosal lining of the gall bladder absorbs fluid and electrolytes thus increasing the concentration of other bile con­stituents.

When the food reaches the duodenum, the duodenal walls secret an enzyme- cholecystokinin which enters the gall bladder along with the blood and causes the walls to contract and release the bile.