Human Growth and Development / Unit 2 HGD 0181 short lesson, about 20 seconds
The Germinal Period
Captions available
The idea
The germinal period runs from conception to about two weeks; the zygote, the single cell formed at conception, begins dividing within a day.
In practice
A blastocyst of a few hundred cells beginning to implant in the uterine wall about a week after conception.
Where people slip
An estimated fifteen percent of pregnancies are lost before or during implantation.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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