In the normal rats on gestational days 15, URS fuses with cloacal membrane, and on gestational days 16 anal membrane ruptures and rectum communicate with the anus.
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美
- 鼠胚胎 15d时尿直肠隔与泄殖腔膜融合。 胚胎 16d肛膜完全破裂 ,直肠与外界相通。