Week 2

Question 1

Day 8

Answer 1

▪️trophoblast continue to differentiate
-SCT produce hCG which is used in pregnancy tests and maintains corpus luteum therefore endometrial wall
▪️bi-laminar disc is distinct and flattens
-epiblast and hypoblast
▪️amniotic cavity is formed

Question 2

Day 9-10

Answer 2

▪️implantation complete
-fibrin plug closes gap
▪️extracellular vacuoles appear in syncytiotrophoblast and join to form lacunae
▪️amnioblast separate from epiblast and organise into amnion (encloses amniotic cavity)
▪️formation of primary yolk sac surrounded by hypoblast

Question 3

Day 11-13

Answer 3

▪️formation of extra-embryonic mesoderm
▪️formation of chorionic cavity surrounded by EEM
▪️primary yolk sack to secondary yolk sac
▪️maternal blood filled lacunae
-primitive utero-placental circulation
▪️formation of primary chorionic villi

Question 4

Week 2 abnormalities

Answer 4

▪️abnormal implantation 
-uterine tube
-outside uterus (ovary, bowel,GI)
▪️molar pregnancy
-hydatidiform mole 
-trophoblast layers proliferate instead of epiblast- no embryo develops