The disc-like tissue embedded in the uterine wall which provides nutrition to the embryo within the womb is known as the placenta.
When the zygote gets attached to the wall of the uterus (implantation), a disc-like tissue is formed. This tissue provides all the nutrition and oxygen to the growing embryo and removes all the waste material as well. This disc-like tissue, known as placenta, is also responsible for conferring immunity to the growing embryo.