part_of part of part of anatomical entity anatomical entity membranous layer extraembryonic membrane https://github.com/obophenotype/uberon/wiki/Modeling-extraembryonic-membranes uberon UBERON:0005631 stuctures homologous to the four extraembryonic membranes appear in mammals [ISBN:0073040584 (Vertebrates, Kardong)] Intrinsic membrane that arises from embryonic germ layers and grow to surround the developing embryo. EHDAA2:0004714 EHDAA2 is a mereological sum. FMA:305915 SCTID:362840007 entire extraembryonic component