1. Aim: How does an embryo develop inside the uterus?

2. How long are humans pregnant?
check out this webpage for videos of development
Females are pregnant for nine months or 38 weeks
During this time, the mother and baby undergo many changes.

3. Embryo vs. Fetus Fetus Embryo (9 weeks-Birth) (Fertilization-9 weeks)
Once the embryo becomes a fetus, all the major organs have begun to form.

4. Where does the embryo develop?
In the uterus - womb
Surrounded by an amniotic sac & fluid for protection from shock

5. Why is the fetus floating in a fluid?
The fetus is surrounded by amniotic fluid and it helps absorb shock

6. What does a developing embryo need?
1. Nutrients for ATP & to build its own body parts
2. Oxygen for ATP

7. Placenta
The placenta is the organ that allows for the exchange of nutrients and wastes

8. Embryonic Waste Products
1. Metabolic waste (from cells)
2. Carbon Dioxide

9. Umbilical Cord
The umbilical cord is responsible for carrying nutrients and oxygen to the developing fetus, and waste away.

10. Fetal Blood Supply The blood from the mom and the embryo NEVER mix.
Materials diffuse between the mother’s blood & the baby’s blood.

11. What happens at around 9 months?
The fetus has developed all its organs and is ready to live in the outside world
The uterine muscles begin to contract and the baby is forced out of the mother.
This process is called:
Labor

12. Prenatal care Good nutrition No smoking Moderate exercise
No drugs, prescription or illegal
No alcohol

13. Don’t get morning sickness: Thalidomide (1950)

14. Fetal Alcohol Syndrome (FAS)
Consuming alcohol during development can cause FAS which has disastrous affects on the CNS.
Includes:
Low birth weight (poor growth)
Small cranium
Organ dysfunction
Failure to thrive
Developmental delays, learning dis.
Facial abnormalities (small eyelid,nose
Mental retardation

15. What trimester is the most dangerous?
The first trimester, because all the organs are forming at this time. Dangerous chemicals can affect cell division.

16. STRUCTURES BY 3rd WEEK Placenta
Placenta
Nervous and endocrine system (starting)
Vital organs forming
Heart is beating

17. FIRST TRIMESTER (3months)
Most major organs formed
Umbilical cord formed
Muscular system developed
Reflexes
Amnion formed

18. SECOND TRIMESTER Tissues become specialized Skeleton forms
Strong fetal heartbeat
At ~6 months the baby can live outside the mom with life support

19. 3rd Trimester Fetus doubles in size Lungs are forming
Sleeps 90-95% of the time
Dreams
Premature if born before 8 months

22. 5 wks; 10 mm