Obstetric and Gynecological Nursing - The Carter Center

Blastocyst
Trophoblast
Inner cell mass
Placenta + Chorion Fetus + Amnion +Umblical cord
The inner cell mass
While the trophroblast is developing into the placenta, which
will nourish the fetus, the inner cell mass is forming the fetus
itself. The cells differentiate into three layers, each of which
will form particular parts of the fetus.
- The ectoderm mainly forms the skin and nervous system
- The mesoderm forms bones and muscles and also the
heart and blood vessles, including those which are in
placenta.
- The endoderm forms mucous memberanes and glands.
The three layers together are known as the embryonic
plate.
The amniotic cavity- lies on the side of the ectoderm; the
yolk sac lies on the side of the endoderm and provides
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