西伯利亚鲟消化道形态学和组织学的初步研究

对人工养殖2龄西伯利亚鲟消化道的形态解剖学和显微组织学结构进行了观察。研究结果表明,西伯利亚鲟的消化道从前至后分为口咽腔、食道、胃、幽门盲囊、十二指肠、瓣肠和直肠,食道与胃的分界不明显,形成一个"食道-胃过渡区",胃分为贲门部、胃体部和幽门部。组织学研究显示:西伯利亚鲟的消化道由内向外一般分为粘膜、粘膜下层、肌层和浆膜四层。其中食道粘膜上皮为复层扁平上皮,含杯状细胞和粘液细胞。"食道-胃过渡区"已有腺体存在。胃上皮细胞为单层柱状上皮细胞,无杯状细胞,胃的粘膜表面有许多上皮凹陷形成的胃小凹,幽门部的胃小凹较贲门部和胃体部深;贲门部和胃体部中含有大量的胃腺,幽门部无胃腺。幽门盲囊的管腔内被向内深入的肌层分割成许多完全或不完全的囊腔;粘膜褶皱和褶皱上的绒毛纵横交错,形成网状。肠上皮均为单层柱状上皮,上皮细胞间分布有大量的杯状细胞;粘膜褶皱的高度和数量、杯状细胞的数量从前至后递减:十二指肠粘膜褶皱细而高,上有许多绒毛;瓣肠粘膜和粘膜下层向管腔内突出并卷曲,形成螺旋瓣;直肠的粘膜褶皱矮且宽。

On morphology and histology of the digestive tract in Siberian sturgeon Acipenser baerii

Morphological and histological studies on the digestive tract of 2-year-old Siberian sturgeon,Acipenser baerii was carried out.Results showed that the Siberia sturgeon's digestive tract had stomato-pharyngeal cavity,esophagus,stomach,pyloric caeca,duodenum,valvula intestine and rectum from the front to the back.There was no obvious dividing line between the esophagus and the stomach,so it formed an "esophagus-stomach transition region".The stomach could be divided into three parts: the cardiac part,the fundic part and the pyloric part.The histological structure of digestive tract was studied using light microscopy.It demonstrated that: the digestive tract of Siberian sturgeon was generally divided into the mucosa,the submucosa,the muscular coats and the serosa from the inside to the outside.The esophagus was covered with stratified squamous epithelium which contained goblet cells and mucous cells.There was gland in the "esophagus-stomach transition region".The stomach mucosa epithelium was formed with a simple columnar epithelium without goblet cell.There are many gastric pits in the mucosa epithelium.The gastric pits in the gasitric pyloricus were deeper than those in the the cardiac part and the fundic part.Enormous stomach glands were present in the lamina propria of the gastric cardiaus and the gastric fundius,and there wasn't any stomach glands in the gasitric pyloricus.There were some complete or incomplete space formed by the muscular coats which came into the lumen in the pyloric caeca,and much mucosa folds and the numerous villus on them crossed together forming reticulates.The intestinal epithelium was single-layered columnar epithelium,including a lot of goblet cells.Both the height and the amount of the mucosa folds and the amount of the goblet cells were descending from the front to the back.The mucosa folds which had a great deal of intestinal villus of the duodenum were taller and thinner compared with the valvula intestines and the rectum.Results proved that both the morphology and the structure of the digestive tract adapted to its function in Siberian sturgeon.The digestive tract also retained pyloric caeca and valvula intestine that existed in teleostean and elasmobranch respectively,which indicated its specificity and the significance in evolution.