香鱼消化道及肝脏的形态结构特征

采用解剖及石蜡切片显微技术观察了香鱼消化道及肝脏的组织学结构。香鱼消化道由口咽腔、食道、胃及肠构成。口咽腔大且狭长,其底壁前部有一对粘膜褶,两颌边缘着生宽扁梳状齿,腭骨及舌骨具齿,犁骨无齿;舌由基舌骨突出部分覆盖粘膜构成,舌粘膜上皮为复层扁平上皮,含有较多的杯状细胞和味蕾。食道、胃及肠均由粘膜层、粘膜下层、肌层及外膜构成。食道粘膜层上皮为复层扁平上皮,杯状细胞发达。胃呈V形,由贲门部、胃体部及幽门部组成,胃壁粘膜上皮为单层柱状上皮,贲门部与胃体部的固有层中有胃腺。肠较短,由前、中、后肠构成,肠壁粘膜上皮为单层柱状上皮,其游离面具微绒毛;上皮细胞间有杯状细胞。幽门盲囊有350～400条,其组织学结构与肠相同。肝脏单叶,外被浆膜;肝细胞形态不规则,肝小叶界限不明显。

Morphology of the digestive tract and liver of Plecoglossus altivelis

The morphological characteristics of the digestive tract and liver in Plecoglossus altivelis were observed by paraffin section and photomicrography techniques. The digestive tract includes the orol-pharyngeal cavity, esophagus, stomach and intestine. The orol- pharyngeal cavity is big, long and narrow; in the front of its bottom wall there are a pair of mucous plait; on the edge of the two jaws there are broad flat pectinate jaw teeth; there are teeth on the palate bone and hyoid bone, but no teeth on the vomer. Tongue is formed by the projecting part of basihyoid covered by mucosa. Tongue mucosa epithelium is stratified squamous epithelium, and contains many goblet cells and taste buds. The esophagus, stomach and intestines all consist of mucous membrane layer, submucosa, muscularis and outer membrane. The mucosa of esophagus is stratified squamous epithelium with developed goblet cells. V-shaped stomach comprises cardia, body of stomach and pylorus. Stomach mucosa epithelium is simple columnar epithelium. There are gastric glands in the lamina propria of cardia and body of stomach. Intestine is short and consists of foregut, midgut and hindgut. The mucous epithelium of intesti- nal wall is simple columnar epithelium and the free surface of it contains a dense array of microvilli. Lots of goblet cells are distributed in the intestinal epithelium. Conjunctive sites of intestines and pylorus contain 350 - 400 pyloric caecums whose histological structure is the same as intestines. The liver is singular and coated by the serosa. The shape of hepatocyte is irregular and the boundaries of hepatic lobules are inconspicuous.