The outermost extraembryonic membrane. [ MP:0002836 MESH:A10.615.284.473 ]

This is just here as a test because I lose it

Term information

database cross reference
  • NCIT:C34124
  • GAID:1299
  • EHDAA:150
  • EHDAA2:0000245
  • FMA:80224
  • CALOHA:TS-0144
  • Wikipedia:Chorion
  • NCIT:C34122
  • VHOG:0000200
  • BTO:0000252
  • UMLS:C0008503 (ncithesaurus:Chorion)
  • UMLS:C1516505 (ncithesaurus:Chorionic_Sac)
  • EFO:0002780
  • EV:0100121
  • MESH:A16.254.403.473
  • EMAPA:16112

uberon_slim, efo_slim, pheno_slim


The outermost extraembryonic membrane.

depicted by

development notes

Extra-embryonic ectoderm

external definition

The outer membrane of the two membranes enclosing the embryo in reptiles, birds, and mammals. In placental mammals it contributes to the development of the placenta[BTO:0000252].

The outer membrane enclosing the embryo in reptiles, birds, and mammals. [TFD][VHOG]

has exact synonym

embryonic chorion


uterine chorion

fetal chorion

chorion (vertebrates)

has related synonym

chorionic sac

chorion frondosum

homology notes

Structures homologous to the four extraembryonic membranes of reptiles and birds appear in mammals: amnion, chorion, yolk sac, and allantois.[well established][VHOG]



taxon notes

The chorion of placentals is bilaminar as in reptiles and birds, but forms from the trophoblast and includes the ajdacent mesodermal layer [ISBN:0073040584]