Department of Anatomy and Cell Biology, University of Cantabria, Santander, Spain.
Anat Rec (Hoboken). 2010 Jul;293(7):1146-54. doi: 10.1002/ar.21154.
The gastrointestinal tract of the African lungfish Protopterus annectens is a composite, which includes the gut, the spleen, and the pancreas. The gut is formed by a short oesophagus, a longitudinal stomach, a pyloric valve, a spiraling intestine, and a cloaca. Coiling of the intestine begins dorsally below the pylorus, winding down to form six complete turns before ending into the cloaca. A reticular tissue of undisclosed nature accompanies the winding of the intestinal mucosa. The spleen is located along the right side of the stomach, overlapping the cranial end of the pancreas. The pancreas occupies the shallow area, which indicates on the gut dorsal side the beginning of the intestine coiling. In addition, up to 25 lymphatic-like nodes accompany the inner border of the spiral valve. The mesenteric artery forms a long axis for the intestine. All the components of the gastrointestinal tract are attached to each other by connective sheaths, and are wrapped by connective tissue, and by the serosa externally. We believe that several previous observations have been misinterpreted and that the anatomy of the lungfish gut is more similar among all the three lungfish genera than previously thought. Curiously, the gross anatomical organization is not modified during aestivation. We hypothesize that the absence of function is accompanied by structural modifications of the epithelium, and are currently investigating this possibility.
非洲肺鱼 Protopterus annectens 的胃肠道是一个复合结构，包括肠道、脾脏和胰腺。肠道由短的食管、纵向的胃、幽门瓣、螺旋状的肠和泄殖腔组成。肠的卷曲始于幽门瓣的背部，向下缠绕六圈后结束于泄殖腔。一种性质不明的网状组织伴随着肠黏膜的缠绕。脾脏位于胃的右侧，与胰腺的颅端重叠。胰腺占据浅的区域，这表明在肠道的背侧开始卷曲。此外，多达 25 个淋巴样结节伴随螺旋瓣的内缘。肠系膜动脉为肠形成一个长轴。所有胃肠道的成分都通过结缔组织鞘相互连接，并被结缔组织和浆膜包裹。我们认为，以前的一些观察结果被误解了，肺鱼肠道的解剖结构在所有三种肺鱼属中比以前想象的更为相似。奇怪的是，在夏眠期间，大体解剖结构没有改变。我们假设功能的缺失伴随着上皮结构的改变，目前正在研究这种可能性。
