Early implantation and embryonic development of the baboon: stages 5, 6 and 7

R. Tarara, A. C. Enders, Andrew G Hendrickx, N. Gulamhusein, J. K. Hodges, J. P. Hearn, R. B. Eley, J. G. Else

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38 Scopus citations


Implantation stages of the olive baboon, Papio cynocephalus anubis, showing embryonic development equivalent to Carnegie stages 5, 6 and 7 of development, were collected by hysterotomy and examined histologically. The younger specimens (stage 5) consisted of a thick trophoblastic plate composed of cytotrophoblast and syncytiotrophoblast with multiple small clefts, and a bilaminar disk embryo with a small slit-like amniotic cavity. An epithelial plaque response was present in the uterine epithelium immediately peripheral to the implantation site, within an area of pronounced uterine edema. The bilaminar embryonic disk consisted of columnar epiblast cells underlying the amniotic cavity, and thickened visceral endodermal cells that form part of the yolk sac. The slightly further developed placenta (stage 6) consisted predominantly of cytotrophoblast including primary villi and syncytotrophoblast lining large spaces containing maternal blood. Secondary placental villi were present in the oldest group (stage 7), and there was modest decidualization of the uterine stroma. An epithelial plaque response persisted, but varied in extent. The sequence of events in early development in the baboon is similar to that in the rhesus monkey insofar as blood space formation and endometrial responses are concerned. However, the plaque response is not so great as in the rhesus; there is no secondary placenta, and the decidual response is slightly more extensive.

Original languageEnglish (US)
Pages (from-to)267-275
Number of pages9
JournalAnatomy and Embryology
Issue number3
StatePublished - Jul 1987


  • Baboon
  • Decidualization (decidua)
  • Developmental stages
  • Epithelial plaque
  • Implantation

ASJC Scopus subject areas

  • Anatomy
  • Embryology
  • Developmental Biology
  • Cell Biology


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