1. Pregnancy, Birth, and Childhood
Lesson 2 – Development Before Birth

2. Ch 19-2 – Development Before Birth
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3. Development Before Birth
What’s happening here?

4. Development Before Birth

5. Development Before Birth
Implantation
when a zygote attaches itself to the wall of the uterus
Embryo
the name for the zygote after implantation (until 9 weeks)

6. Development Before Birth
So how do you know you are pregnant?
Signs of Pregnancy:
Offset of the menstrual cycle
Nausea
Unusual tiredness
Frequent urination
Change of appetite
Breast tenderness ? ? ? ? ? ?

7. Development Before Birth
How is pregnancy diagnosed?
A blood or urine sample
The hormone HCG
is released by the
embryo and present
in the test

8. Development Before Birth
The protective structures of the embryo

9. Development Before Birth
Amniotic Sac
fluid filled sac that surrounds the embryo.
acts like a shock absorber
Protects the growing fetus
Keeps the temperature constant
Placenta
a structure that forms along the lining of the uterus as the embryo implants; “life support system”.
Umbilical Cord
the cordlike structure that connects the embryo and the placenta.
Fetus
the name of the embryo after 2 months.

10. Stages of Embryonic Development

11. Stages of Embryonic Development

12. Stages of Embryonic Development

13. Development Before Birth
Other things to consider about development:
How many sperm actually survive the journey to the egg?
How long is the umbilical cord (on average)?
Is blood ever exchanged between mother and fetus?
Since a fetus doesn’t breathe, how could the mother’s smoking habit harm it?
What options do people have when they have difficulty getting pregnant?