Chatchavalvanich Kannika, Marcos Ricardo, Poonpirom Jintana, Thongpan Amara, Rocha Eduardo
Department of Zoology, Faculty of Science, Kasetsart University, Bangkok, Thailand.
Anat Embryol (Berl). 2006 Oct;211(5):507-18. doi: 10.1007/s00429-006-0103-3. Epub 2006 Jun 17.
We investigated the histology and histochemistry (of carbohydrates and proteins) of the digestive tract of the freshwater stingray Himantura signifier. The alimentary tract consists of a mouth, pharynx, esophagus, stomach (with a descending cardiac and ascending pyloric part), anterior intestine (with an initial portion and a spiral intestine) and posterior intestine, ending in a cloaca. Histologically, three layers--mucosa, muscularis and adventitia/serosa--were defined from the mouth to esophagus and in the posterior intestine, whereas in the stomach and anterior intestine four layers were present, including a submucosa. The epithelial lining of mouth, pharynx and cloaca was of the stratified cuboidal type, whereas that of the esophagus and posterior intestine was stratified columnar. The stomach and anterior intestine were lined by a simple columnar epithelium with microvilli. Goblet cells were observed along the alimentary tract, except in the stomach. In the descending cardiac portion of this organ, gastric glands composed of oxyntic, oxyntic-peptic and peptic cells were observed. The anterior intestine presented a spiral valve with 11 folds, formed by mucosa and submucosa. The posterior intestine was particular in displaying a three-layered muscularis. Mucosubstances secreted along the alimentary tract contained both neutral and acid mucins, but in the stomach only neutral mucins were detected. The stomach presented intense protein content in the epithelial lining of the gastric pits. Enteroendocrine cells were identified in the stomach and intestine. Overall, our data offer a baseline for comparative purposes and future detailed ultrastructural and immunohistochemical studies.
我们研究了淡水黄貂鱼（Himantura signifier）消化道的组织学及（碳水化合物和蛋白质的）组织化学。消化道由口、咽、食管、胃（有下行的贲门部和上行的幽门部）、前肠（有起始部和螺旋肠）和后肠组成，后肠以泄殖腔为终点。组织学上，从口到食管以及后肠可分为三层——黏膜层、肌层和外膜/浆膜层，而胃和前肠有四层，包括黏膜下层。口、咽和泄殖腔的上皮为复层立方上皮，而食管和后肠的上皮为复层柱状上皮。胃和前肠由有微绒毛的单层柱状上皮覆盖。除胃外，沿消化道均观察到杯状细胞。在该器官的下行贲门部，观察到由壁细胞、壁细胞-主细胞和主细胞组成的胃腺。前肠有一个由黏膜和黏膜下层形成的有11个褶皱的螺旋瓣。后肠的特点是肌层有三层。沿消化道分泌的黏液物质含有中性和酸性黏蛋白，但在胃中仅检测到中性黏蛋白。胃小凹的上皮衬里中蛋白质含量很高。在胃和肠中鉴定出了肠内分泌细胞。总体而言，我们的数据为比较研究以及未来详细的超微结构和免疫组织化学研究提供了基线。
