What is a Gallbladder?

WHERE IS THE GALLBLADDER
Gallbladder – an organ that is situated under the right lobe of the liver.

FUNCTION OF GALLBLADDER
It is a small pear-shaped muscular membranous sac stores the bile until needed by the body for digestion. It receives bile from the liver, concentrate it, and discharge it into the duodenum of the small intestine.

SIZE OF GALLBLADDER
This hollow muscular organ is expandable, it is about 7-10 cm long, 3 cm in maximum breadth, and under usual circumstances, it can store about 30-50 ml capacity.

SECTIONS OF GALLBLADDER
It is divided into three sections: fundus, body and neck. The neck tapers and connects to the biliary tree via the cystic duct, which then joins the common hepatic duct to become the common bile duct.

Its inner area absorbs water and inorganic salts from bile, which then becomes 5 – 18 times more concentrated than when it leaves from the liver. Bile acids and other constituents of bile produced in the liver are carried to the gallbladder via the hepatic and cystic ducts.

LAYERS OF GALLBLADDER
The different layers of the gallbladder:
- The epithelium, a thin sheet of cells closest to the inside of the gallbladder
- The lamina propria, a thin layer of loose connective tissue (the epithelium plus the lamina propria form the mucosa)
- The muscularis, a layer of muscular tissue that helps the gallbladder contract, squirting its bile into the bile duct
- The perimuscular (“around the muscle”) fibrous tissue, another layer of connective tissue
- The serosa, the outer covering of the gallbladder that comes from the peritoneum, which is the lining of the abdominal cavity

HOW GALLBLADDER WORKS?
When fatty food gets through from stomach to intestine, the gallbladder is stimulated to contract by cholecystokinin, a hormone released from the lining of the intestine. The concentrated bile is then carried into the intestine through the cystic and common bile ducts. The high concentration of bile acids turns fat into an emulsion that is easily digested by the action of the enzyme lipase from the pancreas and gets absorbed across the intestinal wall. The efficiency of this system is enhanced by the reabsorption of bile acids from the intestine, minimizing the quantity lost in the feces. Reabsorbed bile acids are then carried by the bloodstream back to the liver, where they are available for further recycling into the bile.