Your little blastocyst is now separating into two distinct parts: the amniotic cavity (or yolk sac) and the embryo (your baby-to-be). The yolk sac’s main job is to protect and nourish your baby until the placenta is fully formed. Right now, the placenta is just beginning to take shape, but won’t be complete for another 8 weeks or so. The beginnings of the umbilical cord are visible and partly functional, although it is still not fully formed.
