Scanning Electron Microscope Observation on the Mucosal Epithelium of the Digestive Tract in Siganus canaliculatus

The ultrastructure of mucosal epithelium of the digestive tract in Siganus canaliculatus was examined by scanning electron microscopy. In esophagus,longitudinal folds and V-shape secondary folds of mucosal surface were observed. There were numerous secretory holes and openings of glandular duct. The squamous epithelium cells were flattened,and they were firmly bound to one another. The stomach mucosal folds were arranged vertically,showing rope-like pattern. There were many papillae and no microvillus on the surface of stomach epithelium. The epithelium cells took the shape of pentagon or hexagon,and there were more gastric pits between them. Numerous villi arranged on the surface of intestinal epithelium,showing finger-like or flattened shape. The mucosal epithelium of intestine exhibited gyrus structure,and numerous secretory granules were on the surface. The epithelium cells of intestine were polygon,round or anomalous and had intercellular space. The epithelium structure of the pyloric caeca was similar to that in intestine. In the paper,the relationship between structure of epithelium and their functions was also discussed.