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Back to Topics<<<< Gall bladder is a pear shaped sac lying on the undersurface of the liver between the sixth and eighth segments of liver. Its length is about 7.5 cm to 12.5 cm. it has a capacity of about 30-50ml and stores bile. The gall bladder is divided into fundus, body and neck. The fundus is rounded and usually projects below the inferior margin of the liver. The body lies in contact with visceral surface of the liver and is directed upwards, backwards and to the left. Neck becomes continuous with cystic duct, which turns in the lesser omentum to join the right side of common hepatic duct, to form the bile duct. The muscle fibers in the wall of gall bladder are arranged in a criss-cross manner, being particularly well developed in neck. Mucous membrane contains indentations of mucosa that sinks in the muscle coat called cryptas of Lushka. The peritoneum completely surrounds the fundus and binds the body and neck to visceral surface of liver. Anteriorly: anterior abdominal wall, inferior surface of liver. Posteriorly: transverse colon, first and second parts of duodenum. The gall bladder serves as a reservoir for bile and has ability to concentrate the bile. Bile as it leaves the liver is composed of water (97%), bile salts (1-2%) and pigments (1%), cholesterol and fatty acid. By the active absorption of water, sodium chloride and bicarbonates by the mucous membrane, the hepatic bile which enters the gall bladder becomes concentrated 5-10 times. Bile is delivered to the duodenum as a result of contractions of the gall bladder, which is initiated by entrance of fatty foods into duodenum. The fat causes the relief of cholecystokinin from the mucous membrane of duodenum; the hormone then enters the blood causing the gall bladder to contract. At the same time the smooth muscles around the distal ends of the bile duct and the ampula is relaxed, thus allowing the passage of concentrated bile into the duodenum. Blood supply: The gall bladder is supplied by the cystic artery, a branch of right hepatic artery. In 20% right hepatic artery arises from the accessory cystic artery and occasionally from the duodenal artery. Venous drainage: The cystic veins drain into the portal vein. Lymph drainage: Subserosal and submucosal lymphatic drains into cystic lymph nodes of LUND, which lies in the fork created by the junction of cystic and common hepatic duct, and then from lymph vessels pass to the hepatic nodes along the course of hepatic artery and then to the celiac nodes. Nerve supply: Nerve supply is from sympathetic and parasympathetic vagal fibers from the celiac plexus. Callot’s triangle: During intervention of bile tree, its superior border is the inferior edge of the liver, laterally by cystic duct and medially by the bile duct. Cystic duct: Cystic duct is about 2.5-4 cm long and connects neck of the gall bladder to the common hepatic duct. The mucous membrane of the cystic duct is raised from a spiral fold that continues with the similar fold of the neck of the gall bladder. The fold is commonly called as spiral valve of Heister. The function of the spiral valve is to keep the lumen constantly open. Bile duct: Bile duct is about 6-10 cm long. Bile duct is formed by the union of cystic and common hepatic duct. Supraduodenal portion (2.5 cm long) runs in free edge of lesser omentum on right side, on the right side of portal vein and hepatic artery. Retroduodenal portion is located behind the first part of duodenum into the right side of gastroduodenal artery. Intraduodenal portion lies in a groove on the posterior surface of the head of pancreas where it comes in contact with the main pancreatic duct. Infraduodeodenal portion passes obliquely through the wall of second part of duodenum where it is surrounded by circular muscles, known as sphincter of Oddi. This article has been written by Dr. M. Javed Abbas. If you have any comments please do not hesitate to sign my Guest Book. 01:05 08/02/2003 |