Studies Of Microscopic And Submicroscopic Structure On The Pancreas Islet In Tilapia Nilotica

The type and morphology of the pancreas islet as well as its cells in Tilapia Nilotica were studied in detail by using the microscope, electron microscope and special staining techniques.The pancreas in Tilapia Nilotica which combine with liver, belongs to hepatopancreas. The pancreas islet, without fixed form, scatters in the pancreas. The number and type of pancreatic endocrine cells change following the size of pancreas islet, and some islets only have a few cells. We can distinguish clearly acinar cell of pancreas and pancreas islet by H-E staining, the former was dyed deep, the latter was dyed light. With the help of Gomori aldehyde fuchsine stain, we can find three kinds cells in pancreas islet. There are yellow granules in A cell, purplish red granules in B cell and green or light gray granules in D cell.There are very developed rough surfaced endoplasmic reticulums (RER) which was lamellar arrange in cytoplasm of acinar cells and there are much zymogen granules in cytoplasm where approach the lumen of acinus under the electron microscope. The RER in islet cells are not developed than in acinar cells and other organelles are scare to be seen too. Endocrine granules are small and packeted withmembrane. The size and type of granules are not entirely similar, but they all have a core with differ in density. Secretic granules in B cell are fairly big , cores are various. There is fairly big gap between the core and the limiting membrane; the center of secretic granules in A cell exist compact core and there is no gap between the core and the limiting membrane; Secretic granules in D cell are too much, electron density of granules is lower, and there is no gap between the core and the limiting membrane, what's more, fairly big chondriosome can be seen in the cell.