Morphological Study on the Extrahepatic Biliary Duct System of the Camel (Camelus Dromedarius)

The extrahepatic bile duct system of the camel was studied grossly, histology and histochemically. Specimens of the liver with pancreas attached, together with the cranial duodenal flexure of ten adult dromedary camels were used in this study. There was no common hepatic duct due to the absence of the gallbladder in the camel. The bile duct was partially embedded within the dorsal border of the pancreas and at its terminal course in the pancreatic tissue; it was joined by the main pancreatic duct to form the hepatopancreatic duct before it entered the cranial duodenal flexure, about 20-25 cm caudal to the pylorus. The hepatopancreatic duct penetrated the duodenal wall obliquely, and passed for 2 to 3 cm before it opened by an oval orifice into the lumen of the duodenum. No evidence of a major duodenal papilla. Microscopically, the extrahepatic bile ducts of the camel were characterized by a wide lumen and folded mucosa which contained mucous glands. The ducts were lined with simple columnar epithelium of tall cells and surrounded by dense connective tissue mainly collagenous fibers. The wall of the bile duct contained no muscle fibers and there were no circular muscle fibers in the terminal portion of the duct that could be construed to represent a sphincter. The epithelium lining both the ducts and glands showed PAS-positive material at their apical portion and luminal borders, respectively.