Human Growth and Development / Unit 2 HGD 0183 short lesson, about 20 seconds
The Embryonic Period
Captions available
The idea
The embryonic period runs from about week three to week eight, when the embryo's support structures form alongside its organs.
In practice
The amnion's fluid-filled sac, the placenta and the umbilical cord with its three blood vessels.
Where people slip
The placenta handles respiration, nourishment and waste removal. The chorion becomes the lining of the placenta.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
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