One photo of this beauty is not enough! A section of hypercoiling and furcate insertion (like a fork) but most excitingly a YOLK SAC (Em’s favourite). A yolk sac is what nourishes baby in the early weeks of pregnancy. A few weeks later, the placenta will be fully formed and will take over the transfer of nutrients to the embryo. It’s the outer layer of this sac that develops into the placenta. Can you see why Em loves them?!?