COMPARATIVE ANATOMICAL an‎d HISTOLOGICAL STUDY OF SOME ORGANS IN TWO FISH SPECIES CYPRINUS CARPIOLINNAEUS, 1758 an‎d MESOPOTAMICHTHYS SHARPEYI(GÜNTHER, 1874)(CYPRINIFORMES, CYPRINIDAE)

The present study aims to give some details about the normal anatomical and histological structure of the liver, pancreas and gall bladderin CyprinuscarpioLinnaeus, 1758and Mesopotamichthys sharpeyi(Günther, 1874). Anatomical results revealed that theliver of C.carpiois a reddish-brown in color, located in the anterior part of abdominal cavity and dispersed between most of the intestines, which is divided into two lobes, while in M.sharpeyithe liver is light brown in color located in the anterior part of abdominal cavity and extends to the end of the intestinal tractwith two lobs. The gallbladdersituated in the right side of the liver. Histological results in both species showed that the liver consists of hepatocyte arranged radially around a central vein, separated by blood sinusoids,not divided into distinct hexagonal lobules, no portal traids as in higher vertebrates. The wall of gallbladder consisted of three distinct layers: Tunica mucosa, tunica muscularis and tunica serosa. Microscopic results showed that exocrine pancreatic tissue was diffused type in both species located in liver and consists of acini as "hepatopancreas " however pancreatic tissue diffused between the intestinal coiling in C.carpioand the internal surface of the liver in M. sharpeyi. Endocrine parts of pancreas were observed in few numbers of cell masses in various sizes among exocrine pancreatic cells.