Summary
The maternofetal interface in the placentomes of the sheep placenta consists of a fetal cellular chorion layer whose apical microvilli interdigitate with those of a syncytial layer which borders the maternal connective tissue. Most of the granulated binucleate cells found in the chorion epithelium reach neither its basement membrane nor its microvillar junction apex. However, up to one fifth of the binucleate cells can be shown to be part of or push pseudopodia across the microvillar junction or are located within the syncytium.
The syncytium and chorionic binucleate cells both have a nuclear chromatin structure and distinctive cytoplasmic granules which are not found in any other placental cells. This suggests that most, if not all, of the syncytium is derived by fusion of fetal binucleate cells which have migrated across the microvillar junction from the chorion, and that the immunological maternofetal junction does not lie between chorion and syncytial layers.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Allen, W.R., Hamilton, D.W., Moor, R.M.: Origin of equine endometrial cups. II. Invasion of the endometrium by trophoblast. Anat. Rec. 177, 483–502 (1973)
Amoroso, E.C., Perry, J.S.: The existence during gestation of an immunological buffer zone at the interface between maternal and foetal tissues. Phil. Trans. Roy. Soc. B. 271, 343–361 (1975)
Amoroso, E.C.: In Marshalls Physiology of Reproduction, Parkes, A.S. (Ed) Vol II Placentation. pp. 127–311. London: Longmans Green and Co., 3rd edition 1952
Assheton, R.: The morphology of the ungulate placenta, particularly the development of that organ in the sheep and notes upon the placenta of the elephant and hyrax. Phil. Trans. Roy. Soc. B. 198, 143–225 (1906)
Boshier, D.P., Holloway, H.: The sheep trophoblast and placental function an ultrastructural study. J. Anat (London) 124, 287–298 (1977)
Contractor, S.F., Davies, H.: Effect of human chorionic somatomammotropin and human chorionic gonadotropin on phytohaemagglutinin lymphocyte transformation. Nature New. Biol. 243, 284–286 (1973)
De Ikonicoff, L.K., Cedard, L.: Localisation of human chorionic gonadotrophic and somatommotrophic hormones by the peroxidase immunohistoenzymic method in villi and ammiotic epithelium of human placentas (from six weeks to term). Amer. J. Obs. Gyn. 116, 1124–1132 (1973)
Lawn, A.M., Chiquoine, A.D., Amoroso, E.C.: The development of the placenta in the sheep and goat; an electronmicroscopic study. J. Anat. (Lond.) 105, 557–578 (1969)
Lin, T.S., Halbert, S.P.: Placental localisation of human pregnancy associated plasma proteins. Science (Wash.) 193, 1249–1252 (1976)
Marchesi, V.T., Florey, H.W.: Electron microscopic study on the emigration of leucocytes. Quart. J. Exp. Physiol. 45, 343–348 (1960)
Martal, J., Djiane, J., Dubois, R.: Immunofluorescent localisation of ovine placental lactogen. Cell. Tissue Res. 184, 427–433 (1977)
Padykula, H.H., Taylor, J.M.: Ultrastructural evidence for the loss of the trophoblast layer in the chorioallantoic placenta of Australian bandicoots (Marsupialia, Peramelidae). Anat. Rec. 186, 357–386 (1976)
Porter, D.G., Amoroso, E.C.: In: Scientific foundations of obstetrics and gynaecology. Philipp, E.E., Barnes, J. and Newton, M. (eds) pp. 675–712. London: Heinemann second edition (1977)
Simionescu, N., Simionescu, M., Palade, G.: Open junctions in the endothelium of the postcapillary venules of the diaphragm. J. Cell. Biol. 79, 27–44 (1978)
Steer, H.W.: Ultrastructure of cell migration through the gastric epithelium and its relationship to bacteria. J. Clin. Path. 28, 636–646 (1975)
Steven, D.H., Bass, F., Jansen, C.J.M., Krane, E.J., Mallon, K., Samuel, C.A., Thomas, A.L., Nathanielsz, P.W.: Ultrastructural changes in the placenta of the ewe after fetal pituitary stalk section. Quart. J. Exp. Physiol. 63, 221–231 (1978)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Wooding, F.B.P., Chambers, S.G., Perry, J.S. et al. Migration of binucleate cells in the sheep placenta during normal pregnancy. Anat Embryol 158, 361–370 (1980). https://doi.org/10.1007/BF00301823
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00301823