Development Flashcards
What is gestation?
Time the fetus grows in the uterus
Where does fertilization take place in?
Ampulla of the fallopian tube
What day does fertilization take place?
14-15 of 28-day cycle
How long does fertilization last?
Only 15 hours after ovulation
How old is a two-cell embryo?
30 hours
How old is a 4-cell embryo?
45 Hours
How old is a 8-cell embryo?
60 hours
How old is a morula?
3 days
How many blastomeres in a morula?
16
How old is a blastocyst/blastula?
4 days
When does nidation (implantation) take place?
Day 6
What is a blastomere?
Unit-cell of the embryo
How are blastomeres totipotent?
Each cell could still potentially turn into an individual (or even twins)
When does the human embryo “hatch” out of the zona pellucida?
Late in blastula stage (must hatch in order to nidate)
What will become the embryo proper?
Inner cell mass
What is trophoblasts?
Outer wall of embryo - contributes to placenta
What does trophoblasts do?
Make hCG to keep uterus ready for pregnancy (hCG makes estrogen & progesterone)
What is blastocoel?
Fluid-filled space of the blastocyst
When does nidation (implantation) Occur?
Day 6 after fertilization at blastula stage
