Kordylewski L
Z Mikrosk Anat Forsch. 1983;97(4):719-34.
In the developing intestine of Xenopus the inner circular muscle layer is always thicker and is set up earlier than the outer, longitudinal one. First undifferentiated myoblasts appear between the intestinal epithelium and serosa in the stage 41 (NIEUWKOOP and FABER, 1967). Two crossed muscle layers appear not earlier than stage 50. Then the outer, longitudinal layer consists of single undifferentiated cells, while the inner one is already built of several rows of myocytes. Their ultrastructure and distribution were examined with TEM and SEM. The differentiation of myocytes examined at ultrastructural level was found to be more advanced in the inner layer than in the outer one. However, only after metamorphosis the smooth myocytes of each layer display all the features of mature muscle cells and contain large numbers of the characteristic elements: dense bodies and caveolae. The latter were not found in the larvae and tadpoles. The increase of collagen contents in the submucosa but not between the layers was also observed. Its possible role in the arrangement of the muscular coat is discussed.
在非洲爪蟾发育中的肠道中，内环肌层总是比外环纵肌层更厚，且形成时间更早。最早的未分化成肌细胞出现在第41期（NIEUWKOOP和FABER，1967）的肠上皮和浆膜之间。两个交叉的肌层最早出现在第50期。此时，外环纵肌层由单个未分化细胞组成，而内环肌层已经由几排肌细胞构成。通过透射电子显微镜（TEM）和扫描电子显微镜（SEM）对它们的超微结构和分布进行了检查。结果发现，在内环肌层中，肌细胞在超微结构水平上的分化比外环肌层更先进。然而，只有在变态后，每层的平滑肌细胞才表现出成熟肌细胞的所有特征，并含有大量特征性成分：致密体和小窝。在幼虫和蝌蚪中未发现后者。还观察到黏膜下层而非肌层之间的胶原蛋白含量增加。讨论了其在肌层排列中的可能作用。
