The outermost layer of the mucosa is the muscularis mucosa or muscularis interna, and it's a layer of smooth muscle that contracts and helps break down food.

粘膜层的最外层为粘膜肌层，也可称为内肌层；它由一层平滑肌构成，可帮助碾碎食物。

The mucosa also has three layers of its own: a layer made of stratified squamous epithelium; a layer of connective tissue, called the lamina propria; and a layer of muscle cells, called the muscularis mucosae.

黏膜层本身又由三层结构组成，一层复层鳞状上皮，一层结缔组织，又叫固有层，还有一层肌细胞，又叫黏膜肌层。