PSY 223 Chapter Notes - Chapter 3: Paramesonephric Duct, Amniotic Sac, Umbilical Cord
15 Nov 2016
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Document Summary
The germinal stage is the period of development between conception and implantation of the embryo. A few days into the germinal stage, the dividing cell mass takes the form of a blastocyst, a stage of the germinal period resembling a fluid-filled ball of cells. The inner part of the blastocyst forms into the embryonic disk, the plate-like inner part of the blastocyst that differentiates into the ectoderm, mesoderm and endoderm of the embryo. The outer part of the blastocyst is the trophoblast, which develops into the amniotic sac, placenta and umbilical cord. The umbilical cord is a tube that connects the fetus to the placenta, while the placenta is an organ connected to the uterine wall and to the fetus by the umbilical cord. The placenta serves as a relay station between mother and fetus for the exchange of nutrients and wastes.
