In huso huso esophagus has thin and thick plica covered by squamous epithelium with mucous cells and taste buds. Two types of mucous cells found in epithelium and in both cells they have neutral and acid mucosubstances. There is not muscularis mucosa and in the deep of connective tissue there is nerve fibers and adipose tissue. Tunica muscularis begin as longitudinal fibers, then an external circular is observed and in the end they gradually replaced with smooth muscle and their orientation will change. Three distinct regions can be identified in those fishes that have stomach. Cardia, fundus and pyloric regions. Not all of these regions can be identified in every fish species. The stomach presents both the cranial and pyloric portion lined with a simple columnar epithelium. Tubular branched glands formed by a single type of glandular cell, located along the stomach, are more numerous in the cranial portion. The histomorphological aspects, as well as the histochemical content and distribution of glycoprotein (Gps).in the mucousa of stomach can be also different in every fish species. The pyloric region of the fish stomach may be devoid of gastric glands or may contain specialized glands. The J-shaped stomach has a meshwork of the folds in cardia and longitudinal folds in fundic and pyloric region. All of these regions are lined with columnar epithelium. This epithelium becomes taller toward the pyloric. The gastric pits in pyloric is deeper than the other parts. The tubular branched glands are observed in three regions, but in pyloric they aren\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'t developed and in fundus they are longer. The surface epithelium secrets neutral Gps but the cells of pits and mucus neck cells secret acid and neutral Gps.

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