Histological observation of the digestive system of Mauremys mutica

The histological characters of oral-pharyngeal cavity,esophagus,stomach,small intestine and large intestine of Mauremys mutica were studied by paraffin section and microphotograph techniques.The results showed that except for oral-pharyngeal cavity,the digestive tract includes four layers,namely mucous layer,tunica submucosa,muscular coat and tunica externa.The difference of each part of digestive tract mainly exists in mucous layer.The epithelia of stomach and small intestine are simple columnar cells.The epithelia of esophagus and large intestine are stratified columnar epithelia.The tongue is salmon pink and it is fixed.The esophagus is distensible. There are many gastric glands in the saclike stomach and many plicae on the inner wall of stomach.The small intestine is the main part of digestive tract.The inner wall of intestine has a lot of villi,while the large intestine has folds but no villi.