part of part of develops_from morula unilaminar epithelium trophectoderm BTO has this has part of the trophoblast VHOG:0000979 EHDAA:56 distinction between trophectoderm and trophoblast unclear/inconsistent in many sources outermost layer of cells in the blastodermic vesicle, which will develop into the trophoblast layer and then contact the endometrium and take part in establishing the embryo's means of nutrition BTO:0001840 The outer cellular layer of the mammalian blastocyst. [Evolution, Fourth_Edition_(2006)_McGraw-Hill, Function, Vertebrates:_Comparative_Anatomy, p.750, see_Kardong_KV][VHOG] (...) the trophoblast develops rapidly so that contact may be made with the maternal uterine tissues when conditions are appropriate. We have here an excellent example of an embryonic adaptation, the development of a structure never present in either adult or embryo of 'lower' vertebrates.[well established][VHOG] EHDAA2:0002091 trophectodermal uberon UBERON:0004345 EMAPA:16046 extraembryonic membrane extraembryonic epithelium