In vertebrate embryos, the cloacal structure gradually differentiates into distinct parts of the urinary and digestive systems.

cloacal 是形容词，来自名词 cloaca（泄殖腔）。cloaca 源自拉丁语，指动物体内泌尿、生殖和消化系统共用的腔室结构。cloacal 表示"与泄殖腔相关的"。