Embryology

Question 1

Phases of Embryogenesis

Answer 1

Gametogenesis
Fertilisation
Cleavage
Gastrulation
Embryonic folding
Organogenesis
Foetal period

Question 2

Gametogenesis

Answer 2

Formation of Gametes
- Spermatogenesis
occurs at puberty and continues
22+X or 22+Y
- Oogenesis
primary oocytes begin meiosis in week 28 to 30 but arrest in prophase until puberty

Question 3

Fertilisation

Answer 3

Union of gametes
Sperm + Oocyte = Zygote
diploid single celled embryo

Question 4

Cleavage

Answer 4

Period of rapid mitotic cell division with no increase in size
Blastomeres divide to form Morula followed by Blastocyst
Day 1-4

Question 5

Gastrulation

Answer 5

Formation of germ layers
-endoderm
-mesoderm
-ectoderm
Body axis established

Question 6

Embryonic folding

Answer 6

Formation of body plan
Gut tube forms

Question 7

Organogenesis

Answer 7

Formation of organs and organ system
End of embryonic period to foetal period

Question 8

Fetal period

Answer 8

Week 9 to birth
Growth in 2nd trimester
Weight gain in 3rd
Tissues mature and become functional
Sexual differentiation
Initial bone laid down and connections made in CNS