1. PREGNANCY The presence of a developing offspring in the uterus.
Fertilization: egg + sperm=zygote
Occurs in uterine tube
Ectopic/Tubal pregnancy: zygote does not drop into uterus

2. Early embryonic development
Zygote undergoes mitosis, giving rise to smaller and smaller cells during cleavage. (30 hrs)
Morula (16 cells) moves down uterine tube and implants in endometrium.
Once implanted, the offspring is called an embryo through week 8. Fetus week 8-40.
Placenta forms from cells of embryo and endometrium.
Organ of exchange of nutrients, gases, and wastes b/w maternal blood and embryo blood
Secretes hormones

4. Hormones hCG (human chorionic gonadotrophic) Prevents pregnancy loss
Relaxin
Relax ligaments of pelvic joints
Inhibit contraction of uterus
Estrogen & progesterone
Maintain uterine wall and inhibit secretion of FSH and LH

5. Embryonic stage
Week 2-8
Placenta and main internal and external body structures develop
Amnion (membrane w/in placenta) develops around embryo
Amniotic fluid fills the space b/w amnion and embryo
Umbilical cord forms from amnion
- suspends embryo in cavity
-exchange blood b/w embryo and placenta
-contains 2 arteries and 1 vein
End of week 8 embryo is recognizable as a human

6. MONTH 2
MONTH 5
MONTH 3
MONTH 7
MONTH 4

7. Fetal Stage
Week 8-birth
Fetus is full term after 38 weeks
MONTH 9

8. Milk production Birth process
Decrease in progesterone initiates birth process
Pituitary gland releases oxytocin to stimulate uterine muscles to contract
Afterbirth (placental tissues) are expelled following birth
Milk production
Hormone prolactin stimulate mammary gland to produce milk
Colostrum: substance first released from gland that contains proteins and antibodies

9. Twins Fraternal: 2 different eggs and 2 different sperm
Results in 2 genetically different offspring
Identical: Fertilized zygote slits during cleavage
Results in 2 genetically identical offspring