Human Growth and Development / Unit 2 HGD 0176 short lesson, about 20 seconds
Conception
Captions available
The idea
Conception is the union of a sperm and an egg; luteinizing hormone triggers the egg's release, and progesterone prepares the uterine lining.
In practice
Sperm surviving up to five days, and an egg open to fertilisation for about twelve hours.
Where people slip
Only one sperm penetrates the egg, which then becomes impenetrable to the rest.
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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