Now, surrounded by the muscularis externa is the submucosa, which consists of a dense layer of tissue that contains blood vessels, lymphatics, and nerves.

在肌层包裹下的是粘膜下层；它由一层致密组织构成，其中含有血管、淋巴和神经。

Beneath the epithelium, there's another layer called the basement membrane made of tough connective tissue, and below that is the lamina propria which has yet more connective tissue that houses blood vessels, lymphatics, nerves, and immune cells.

在这层上皮下面的是另一层称为基底膜的结构，由坚硬的结缔组织构成，再往下是固有层，其包含更多结缔组织，容纳了血管、淋巴管、神经和免疫细胞。

The synovium's composed of loose connective tissue, blood vessels, lymphatic vessels, and on the surface—" Type A" cells that clear cellular debris and " Type B" cells that produce components of synovial fluid, which helps lubricate the two articular surfaces.

滑膜由松散结缔组织、血管、淋巴管组成；在滑膜表面，A型细胞清理细胞碎屑，B型细胞产生滑液成分，滑液能够润滑两块关节的表面。