part_of part of part of develops_from develops from develops from has developmental contribution from has developmental contribution from contributes to morphology of membranous layer embryonic cloaca ectoderm endoderm primitive streak cloacal membrane http://upload.wikimedia.org/wikipedia/commons/d/d2/Gray991.png uberon EHDAA:214 EHDAA2:0000257 EMAPA:16832 UMLS:C0231056 EHDAA:2933 embryonic cloacal membrane The membrane that covers the embryonic cloaca, formed by the union of proctodeal (anal pit) ectoderm and cloacal endoderm, with no intervening mesoderm; the urorectal septum joins the cloacal membrane and divides it into an anal membrane and a urogenital membrane; the point where the urorectal septum intersects the cloacal membrane is the future site of the perineal body; proliferation of mesoderm and ectoderm around the cloacal membrane produces primordial tissues of the external genitalia in both sexes: the genital tubercle, genital folds, and genital swellings. UBERON:0006217 membrana cloacalis VHOG:0001198 A membrane that separates the proctodeum and the hindgut in the early embryo. [Evolution, Fourth_Edition_(2006)_McGraw-Hill, Function, Vertebrates:_Comparative_Anatomy, p.497, see_Kardong_KV][VHOG] Wikipedia:Cloacal_membrane SCTID:308826008 NCIT:C34128 In mammals, the cloaca exists as an embryonic structure that undergoes septation to become distinct urethral, anal, and genital orifices.[well established][VHOG] FMA:295525