ANATOMICAL STUDY OF THE BILIARY DUCT IN BLUE DOLPHINE (STENELLA COAERULEO-ALBUS)

Blue white dolphine (Stenella coaeruleo-albus) lacks the gall bladder and has the biliary duct which consists of the hepatic, common heaptic and hepato-pancreatic ducts. In the adult, the duct from the liver to the junction of the duodenum was about 5 cm long and its length in the duodenal wall was 4 to 5 cm.It was demonstrated by maceration method and histological investigation that the muscle layers of the duct consist of four muscle layers, i. e., from the serosa inwards the longitudinal, circular, longitudinal and circular muscle layers, respectively.The first longitudinal muscle layer originates from the duodenal circular muscle, surrounds the duct and goes up to the junction of the pancreatic duct. The second circular muscle exists in the total length of the biliary duct and connects with the duodenal circular muscle. The third longitudinal muscle is the proper biliary muscle and is thicker in the orifice of the duct, extends 1 cm out of the duodenal wall and is independent of the duodenal muscle. The fourth circular muscle layer is the submucosal muscle.The ganglion cells are located abundantly between every muscle layers of the hepato-pancreatic and in the submucosal layer along the common hepatic and hepatic ducts.