巴西彩龟消化道组织学的初步观察

Histological Observation of the Digestive Tract of the Tortoise,Trachemys scripta

巴西彩龟的消化道管壁由内向外依次由粘膜、粘膜下层、肌层和浆膜4层结构组成。食管、胃和大肠有纵行粘膜皱襞,小肠无皱襞但有绒毛。食管上皮和肠上皮为复层柱状上皮,胃上皮为单层柱状上皮。消化道粘膜固有层内分布有淋巴细胞,虽然淋巴细胞有聚集现象,但没有形成典型的淋巴小结。无食管腺和肠腺,虽然有胃腺但胃腺细胞分化不明显,说明巴西彩龟消化道的组织分化程度较低,在系统发育中处于较低等地位。

The wall of the digestive tract of Trachemys scripta was made up of four layers,including the mucosa,submucosa,muscularis,and serosa,from inside to outside. There were longtitudinal folds in the esophagus,stomach and large intestine,while villi instead of folds were found in the small intestine. Mucosal epithetlium consists of stratified columnar cells in the esophagus and intestine,and simple columnar cells in stomach. There were lymphocytes but no lymphoid nodules in the proper lamina of digestive tract.There were gastric glands in the stomach,whereas differentiation of cells in this gland was not obvious. The esophageal glands and intestinal glands were not found. The low level of tissue differentiation in the digestive tract of the tortoise reflected in some degree the relatively low position of this animal in the phylogeny.