Full-term placenta

Placenta can be identified from recognition of structures of its maternal and foetal parts (most slides show at least one of these components, the chorionic plate or decidua basalis) and of structures of the intervillous space. This space is hidden between both plates, contains the maternal blood, chorionic villi and rare decidual septa. Decidual septa consist of relatively large polygonal decidual cells with a pale cytoplasm; these cells occur mainly in the decidua basalis. Chorionic villi have a specific structure. Their placental barrier in the full-term placenta is formed by the continuous syncytiotrophoblast, mesenchymal connective tissue and endothelium of blood vessels (blood vessels are numerous and touch the edges of villi - in such areas the barrier is reduced to syncytiotrophoblast and endothelium. Cytotrophoblast is discontinuous - only rare (Langhans) cells are left in the villi.