trophoblast layer

trophoblast layer (trof´oblast),

n the layer of peripheral embryonic cells from which the placenta is formed.
References in periodicals archive ?
While not yet proven, these proteins may mediate the entry of viruses such as Zika, enabling them to cross the placental trophoblast layer.
It has been proposed that a breach in the trophoblast layer lining the chorionic villi may result in contact of Hofbauer cells (specialised fetal macrophages) with maternal blood and amniotic fluid.
Whereas chorion is derived from the trophoblast layer, the amnion is derived from the epiblast as early as 8 days after fertilization.