%0 Journal Article
%T Physiology and Pathophysiology of the Biliary Tract: The Gallbladder and Sphincter of Oddi¡ªA Review
%A Jose Behar
%J ISRN Physiology
%D 2013
%R 10.1155/2013/837630
%X The biliary tract collects, stores, concentrates, and delivers bile secreted by the liver. Its motility is controlled by neurohormonal mechanisms with the vagus and splanchnic nerves and the hormone cholecystokinin playing key roles. These neurohormonal mechanisms integrate the motility of the gallbladder and sphincter of Oddi (SO) with the gastrointestinal tract in the fasting and digestive phases. During fasting most of the hepatic bile is diverted toward the gallbladder by the resistance of the SO. The gallbladder allows the gradual entry of bile relaxing by passive and active mechanisms. During the digestive phase the gallbladder contracts, and the SO relaxes allowing bile to be released into the duodenum for the digestion and absorption of fats. Pathological processes manifested by recurrent episodes of upper abdominal pain affect both the gallbladder and SO. The gallbladder motility and cytoprotective functions are impaired by lithogenic hepatic bile with excess cholesterol allowing the hydrophobic bile salts to induce chronic cholecystitis. Laparoscopic cholecystectomy is the standard treatment. Three types of SO dyskinesia also cause biliary pain. Their pathophysiology is not completely known. The pain of types I and II usually respond to sphincterotomy, but the pain due to type III usually does not. 1. Introduction This paper reviews the anatomy and physiology of the extrahepatic biliary tract as well as the pathophysiology and clinical symptoms of the inflammatory and functional disorders of its two key structures: the gallbladder and the sphincter of Oddi. There is also a brief description of generally accepted treatments for these conditions. The extrahepatic biliary tract is a closed system designed to collect, store, and concentrate bile secreted by the liver and that is intermittently delivered to the duodenum through the bile ducts. Bile contains bile salts, a key component involved in the digestion and absorption of fats and liposolubles vitamins, and has other constituents that participate in the enterohepatic circulation including cholesterol (Ch), the most important one from the pathological point of view. These motor functions of the biliary tract are closely integrated with the rest of the digestive system by neurohormonal mechanisms that include the vagus and splanchnic nerves and various hormones among them cholecystokinin (CCK). They control the biliary motor activity during fasting and digestive periods. 2. Anatomy and Physiology 2.1. The Gallbladder The gallbladder is a thin-walled sac usually placed between both hepatic lobes
%U http://www.hindawi.com/journals/isrn.physiology/2013/837630/