ABSTRACT
Objective To observe the ultrastructure of pancreas in the bustard( Otis tarda limaells) . Methods Three bustard's pancreas were observed with electron microscope. Results The exocrine secretory units of bustard's pancreas contain a lobulated tubulo acinar gland in which the lobulation is not so distinct as that of the mammalian gland due to the lack of interlobular connective tissue septa.The space between lobular pancreas is lined directly with pancreatic cells as the duct.Single long spindle shaped connective tissue cell could only be seen among three lobules and its cytoplasm becomes slender and stretches into the space between lobules as a distinct intermediate dense line.The exocrine secretory cells can be divided into two kinds of dark and light.In the light cell,particularly in swelled up rER with very little density are filled the greater part of the cytoplasm and made the cell appearance much lighter than other cells.\;The endocrine cells are divided into two types that are dispersed in pancreatic singly and clustered into pancreatic islets.The dispersed endocrine cells contain a lot of moderate dark electron dense granules in their process near basement membrane.There are two types of islets——A islet and B islet in the bustard pancreas.A islets comprise only one cell type with moderate electron density that contains dark endocrine granules.B islet contains two cell types:B and D cell.B cells are the most numerous cells with a long ovoid nucleus and contains two or three types of granules in the cytoplasm.D cells are relatively rare and can be seen in the periphery nearby basement membrane.Cells keep close to each other and desmosomes can be seen within the islet.The endocrine cells closely contact exocrine cells without basement membrane in the periphery partly.Conclusion\ These are some structural characteristics that adapt to fly and that are different from other animal in bustard's pancreas.