Fetal Placenta The placenta is a fetomaternal organ. The functional unit of the fetal placenta is the fetal cotyledon. The mature human placenta has about 120 fetal cotyledons grouped into visible lobes (frequently and somewhat confusingly termed ‘maternal cotyledons’). Each cotyledon contains a primary villus stem arising from the chorionic plate and supplied by primary branches of fetal vessels. The primary stems […]