英语语法分析

The submucosa and muscularis, however, are still intact.

然而，黏膜下层和肌层仍然保持完整。

The muscularis mucosae derived from the muscle stem cells in the submucosa.

黏膜肌层起源于黏膜下层的肌肉干细胞。

Muscularis was comparatively thick and circular muscle was especially developed.

肌层较厚，环形肌特别发达。