Morphogenesis and fine structure of the near-term placenta of Talpa europaea: I. Endotheliochorial labyrinth.
Morphological studies of placentation of Talpa europaea confirm an antimesometrially orientated discoidal and chorioallantoidic placentome. This placentome, near term, shows a villous labyrinthine zone with interspersed haematomal areolae on its fetal side, a centrally located fetomaternal junctional zone, and a uterine gland zone towards the myometrium. As shown by light and electron microscopy the interhaemal membrane in the labyrinthine zone develops to an endotheliochorial placentation type. It consists of a prominent maternal endothelium, a distinct interstitial layer, which contains some endometrial debris and is interrupted by some endotheliochorial contact points, a bilayered trophoblast with a thin syncytial and a larger cytotrophoblastic component, and a small fetal endothelium. Disintegration of endometrial epithelium takes place at the areolar glandular mouths and in the junctional zone where a decidual cell reaction can also be observed, but no decidual cells become integrated into the labyrinth. In the spectrum from epitheliochorial to haemochorial placentation, Talpa europaea exhibits a less endotheliochorial type of placentation than is the case with carnivores.
D000482:Allantois / Q000033:anatomy & histology; D000818:Animals; D002823:Chorion / Q000033:anatomy & histology; D007312:Eulipotyphla / Q000033:anatomy & histology*; D005260:Female; D008854:Microscopy, Electron; D008971:Moles / Q000033:anatomy & histology*; D010920:Placenta / Q000033:anatomy & histology*; D010929:Placentation; D011247:Pregnancy