The pleural membrane is made up of two layers.

胸膜由两层构成。

Each pleural cavity is lined by a pleural membrane that is composed of two layers.

每个胸膜腔由两层脏壁构成的胸膜层构成。

Organs are covered by pleural membranes, which essentially prevents the organs from rubbing all over each other.

器官被胸膜覆盖，这基本上可以防止器官相互摩擦。

In summary, each pleural cavity is defined by a space surrounding each lung and lined by a pleural membrane.

总之，每个胸膜腔由包饶肺和胸膜层间的间隙构成。

Each pleural cavity is defined by a space surrounding each lung and is lined by a pleural membrane.

每个胸膜腔由肺周间隙限定，内有胸膜。

The pleural membranes secrete a lubricating fluid which allows them to move freely against each other during ventilation, like pistons within a cylinder of an engine.

胸膜分泌润滑剂使它们在通风系统里更好的运动，像引擎里的活塞和汽缸一样。