248 



UROGENITAL SYSTEM 



the spaces occur the syncytial giant cells mentioned above. It is in the plane of 

 this layer that the separation of the placenta takes place at birth. 



The basal plate, or compact layer of the decidua basalis, is composed of a con- 



Syncytium 



Cuboidal cells of Ihe basal 

 layer 



Connective tissue 



•zj^-^tf&J^WfX; Blood-vessel containing 



^^^'^XS-fSMsh nucleated red corpuscles 



Epithelium 

 Epithelial nucleus 



Capillaries <$■'- 



Syncytial knot - 

 Small artery - 



Oblique section of the epithelium 

 B 



Syncytial knot 



Epithelium 



Small vein 



Capillary 



Syncytial knot 



Fig. 241. — Transverse sections of chorionic villi; A, at the fourth week; . B, C, at the end of pregnancy 



(Schaper in Stohr-Lewis). 



nective tissue stroma containing decidual cells, canalized fibrin and persisting 

 portions of the epithelium of the villi. The canalized fibrin is believed to be 

 formed both from the syncytial trophoderm of the villi and from the modified 



