Embryology

Question 1

Week 1

Answer 1

Zygote divides into 32 cells (morula) –> blastocyst –> implants in posterior superior wall of uterus

Question 2

Week 2

Answer 2

Bilaminar Embryo:

1. Epiblast (floor of amniotic cavity)
2. Hypoblast (primary yolk sac)

Placenta:

1. Synctiotrophoblast (hCG, hPL)
2. Cytotrophoblasts

Question 3

Week 3

Answer 3

Trilaminar embryo: ectoderm/mesoderm/endoderm

Question 4

Week 3-8

Answer 4

Organ systems develop

1. Notochord –> neural tube formation from overlying ectoderm
2. Heart begins to contract (4)
3. Susceptibility to teratogens

Question 5

Week 8

Answer 5

Movement begins

Question 6

Week 10

Answer 6

1. Genitalia decided
2. Alar plate –> dorsal, sensory
3. Basal plate –> ventral, motor