1. Fertilization
At fertilization, zygote forms protective coating to keep other sperm out Divides to become…. Blastocyst, which attaches to lining of uterus during implantation (1 week)

2. Some cells divide to become…
Support structures:
Placenta-
Provides oxygen, nutrients, and water
by diffusing molecules across membranes
between mom and baby’s blood
Umbilical cord-
Transports nutrients to baby
and waste to mom
Amniotic sac-
Protects baby and keeps at correct temperature for growth

3. 8 Weeks in Utero

4. 12 Weeks in Utero

6. Other cells divide to become:
The embryo (early development), which divides into three tissue layers
Stem cells- can
make any one of
220 different body
cells

7. 3 Tissue Layers Differentiate
Respiratory and digestive systems
Muscles, bone, blood vessels, skin
Nervous system, sense organs, mouth

8. Fetus Becomes fetus after 8 weeks of development
All organs are in place,
but need to further develop
Head develops at 9 weeks
Fetus begins to move at 5 months (mom feels)
Eyes open at 7 months
Fetus moves into head-down position and ready for birth at 9 months (37-40 weeks)
12-14 week fetus model

9. Pre-Labor Irregular contractions from upper part of uterus
Mucus plug sealing cervix is discharged (bloody show)
Amniotic sac ruptures and discharges water

10. 3 Stages of Labor 1- Cervix dilates 10 cm & effaces (thins)
2-Baby born
(7- 7/12 lbs, inches)
3- Placenta, umbilical cord, sac pushed out (Afterbirth)

11. Incision into abdomen to remove baby
Cesarean Section
Incision into abdomen to remove baby
25-33% of births in U.S. are C-Section
Why?
Hips too narrow
Baby in distress
Umbilical cord wrapped
around neck
Vaginal infections
Placenta previa
Baby in breech position
Women may have up to 3-4 c-sections

12. Breech Presentations

13. Twins Identical vs. Fraternal
Identical- one egg fertilized by one sperm, copies and splits (must be same sex)
Fraternal- two eggs fertilized by two sperm