真鲷幼鱼消化道组织学研究↑（*）

６月龄真鲷（Ｐａｇｒｏｓｏｍｕｓｍａｊｏｒ）幼鱼通过解剖，切片、染色和显微摄像，结果表明：整个消化道从解剖水平可以分为口、口咽腔、食道、胃、肠及直肠等６个功能区。口部有犬齿、臼齿和不规则的粒状齿；口腔内有咽（含咽齿）及鳃耙，鳃耙形成了对食物颗粒的屏障，面向食管保护鳃丝；短的食管起源于咽腔，终止于胃，两者间没有明显的解剖上的差别；Ｙ型的胃分为贲门部、幽门部和胃盲囊３部分。组织学观察可见：胃由单层柱状上皮细胞组成，在贲门区和幽门区的上皮层下面，具有相似细胞组成的胃腺；有４个幽门盲囊，幽门盲囊与肠组织结构基本一致。胰腺管和肝管从幽门盲囊的基部生出。肠道短，肠道前部起源于幽门括约肌之后，在肠瓣处变窄，使整个肠道分为肠和直肠两部分；肠与直肠相比粘膜上有较多的褶皱；肠道上皮由柱状上皮细胞和粘液分泌细胞组成，粘膜下层有致密的结缔组织和大量嗜酸性颗粒的细胞。

Anatomical and histological studies on the digestive tract of juvenile Pagrosomus major

Anatomical studies show that the digestive tract of 6-month-old Pragrosomus major is composed of 6 parts:mouth,oral-pharyngeal cavity,oesophagus,stomach,intestine and rectum.The fish has canine teeth,molar teeth and other transition teeth at this age.There is no obvious difference in structure between the oesophagus and the stomach.The Y-shaped stomach is composed of 3 parts:cardiac part,pyloric part and caecum gastricum. In histology, the stomach is constituted by single-layer columnar epithelium, and the similar tubular gastric glands present in the cardiac and pyloric region which is characterized by 4 caeca.The pancreatic duct and hepatic duct connects the base of the caeca.The intestine begins from the pyloric stomach and gets narrow in the lower region of the intesine where the mucosa forms an inner funnel-like valve. The intestine is short, with lots of vacuoles full of eosinophilic granules.