part of part of develops from has developmental contribution from contributes to morphology of membranous layer embryonic cloaca ectoderm endoderm primitive streak 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 EHDAA:214 EHDAA2:0000257 EMAPA:16832 VHOG:0001198 Wikipedia:Cloacal_membrane SCTID:308826008 EHDAA:2933 NCIT:C34128 FMA:295525 embryonic cloacal membrane