大鸨(Otis tarda limaells)胰腺超微结构研究

STUDIES ON THE ULTRASTRUCTURE OF PANCREAS IN BUSTARD (Otis tarda limaells)

目的 观察大鸨胰腺超微结构 ,探讨大鸨胰腺功能。 方法 透射电镜观察 3例大鸨胰腺。 结果 大鸨的胰外分泌部为管泡状腺 ,腺小叶由于缺乏叶间结缔组织而界限不如哺乳动物的明显。叶间隙似导管 ,小叶间导管管壁简化以至由胰腺分泌细胞代替。仅在 3个小叶间能见到单个长梭状结缔组织细胞 ,其胞质变细伸展进入两叶间隙中间构成 1条中等密度线。外分泌细胞可分为明暗两种。胰的内分泌细胞呈岛状或单个散布于胰外分泌腺中。胰岛分A和B两种 ;A胰岛仅由A细胞构成。B胰岛主要由B和D两种细胞构成 ,其中B细胞数量多 ;D细胞含量少。

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.