贝氏高原鳅消化道的结构

应用解剖学、组织学、组织化学以及透射电镜技术等方法,对贝氏高原鳅Triplophysa bleekeri消化道的结构进行了详细观察.结果表明:贝氏高原鳅消化道由口咽腔、食道、胃、肠和肛门5个部分组成.口咽腔宽阔,顶壁粘膜层粘液细胞和味蕾丰富,底壁棒状细胞含量较多.食道粘膜上皮为复层扁平上皮,上皮细胞顶端有短微绒毛,胞质内常见线粒体,偶见粗面型内质网、滑面型内质网、高尔基复合体和溶酶体.上皮细胞之间夹杂大量粘液细胞,有发达的微管泡系统.基膜内有少量的纤维细胞、网状纤维以及大量胶原纤维束.肌肉层为横纹肌,环肌发达.胃为"V"形,粘膜上皮为典型单层柱状上皮.上皮细胞内含大量分泌颗粒,PAS反应呈强阳性,线粒体发达,多位于细胞基底部.粘膜层无杯状细胞,但贲门和胃体固有膜内具有发达的单管状腺体,胃腺细胞内含大量酶原颗粒、线粒体和粗面型内质网,胃腺细胞周围有发达的微管泡系统.胃体肌肉层变化较大:近贲门部内层为纵肌,外层为环肌;胃体中部内为薄层环肌,外为厚层纵肌;近幽门部内层为环肌,外层为纵肌.肠绕胃呈"φ"形,粘膜皱襞发达,单层柱状上皮游离面有很多微绒毛.上皮细胞之间分散有大量的粘液细胞,其内充满均质的分泌颗粒;整个肠段,粘液细胞自前向后数量逐渐减少.粘膜层细胞间有大量空泡状结构,近基膜处形成发达的微管泡系统.肛门为半开放结构,粘膜上皮为复层扁平上皮,粘膜下层为致密结缔组织,由较厚的横纹肌层支持.

Study on the Structure of the Digestive Tract in Triplophysa bleekeri

Anatomical,histological,histochemical and TEM methods were used to observe the structures of the digestive tract in Triplophysa bleekeri.The digestive tract in T.bleekeri is composed of oral-pharyngeal cavity,esophagus,stomach,intestine and anus.The oral-pharyngeal cavity is wide and the upper wall contains plentiful mucous cells and taste buds while the bottom contains club-like cells.There are short microvilli on the top of stratified squamous epithelial cells of the esophagus.Mitochondria are often seen while rough endoplasmic reticulum,smooth endoplasmic reticulum,Golgi complex and lysosome are occasionally detected in the epithelial cells.A large number of mucous cells are among the epithelial cells and there is a well-developed tublovesicular system.A few fibrocytes and reticular fibers and many bundles of collagen fibers exist in the basement membrane.The muscle layer consists of striated muscles and the circular muscles are developed.The simple columnar epithelial cells of the V-shaped stomach contain a large number of secretory granules with a strongly positive PAS reaction,and plentiful mitochondria are located in the lower part of the cells.There are no goblet cells in the mucosa,but lots of single tubular glands are located in the cardia and the body of the stomach.The gastric glandular cells contain a large number of zymogen granules,mitochondria and rough endoplasmic reticulum and the tublovesicular system is arranged around the gastric glandular cells.The muscle layers of the body of the stomach change greatly: near the cardia part,the inner is longitudinal and the outer circular;in the midst,the inner is thin and circular but the outer thick and longitudinal;near the pyloric part,the inner is circular and the outer longitudinal.The intestine circles around the stomach are "φ" in shape and there are developed mucous folds.A large number of microvilli stick out of the free parts of simple columnar epithelial cells.Many mucous cells full of homogenic secretory granules are among the epithelial cells and their number becomes smaller from the anterior to the posterior of the intestine.There are developed vesicular structures among the cells of mucosa,and a tublovesicular system is formed near the basement membrane.The structure of the anus is semi-opened,which has a stratified squamous epithelium.A dense connective tissue of the submucosa is supported by the thick striated muscle layer.