-
1 hour
Fertilization -
Fertilized Egg
Occurs when the sperm meets the egg -
12 hours
Pro-nuclei join together -
Zygote State
Occurs when the nuclear membrane of the ovum disappears and 23 male chromosomes meet 23 female chromosomes, both nuclei double to 46 chromosomes and then fuse. -
30 hours
1st round of mitosis -
40 hours
2nd round of mitosis -
50 hours
3rd round of mitosis -
Morula Formed
-
Embryonic stage begins
Occurs when the third cleavage occurs and forms a morula -
6th Day
64 cell embryo called a blastocyst -
8 Days
Implantation -
Hatching
-
10 Days
Ectopic pregnancy could occur -
Day 12
Disc with streak on the underside forms mesoderm -
Day 12
HCG beginsto be secreted -
Day 15
First missed period -
16 Days
Neural tubes forms -
22 Days
Heart begins to beat, arm, and leg buds appear. Yolk sac makes RBCs -
Day 35
Face plates forming -
Day 36
Cleft lip or palate may occur -
Week 6
Muscles form, bent neck, webbed hands & feet, and segmented back -
Day 50
Amniocentesis could be performed -
Day 50
Genitalia begins to differentiate, eyelids fuse, and amnion surrounds fetus -
Fetal stage begins
Occurs when all organs are formed -
Week 9
Chorionic villi sampling could be performed -
6-7 Months
Eyes open, fat added under skin, and head out of proportion to the body
