Implantation, Placentation And Hormornal Changes In Pregnancy

Question 0

What is a chorion?

Answer 0

The chorion becomes the placenta

Question 1

What are trophoblasts?

Answer 1

Cells of blastocyst that invade endometrium and myometrium 
Secrete bHCG (human chorionic gonadotrophin)

Question 2

What is the amnion?

Answer 2

The layer that becomes the amniotic sac

Question 3

What happens during day 5-6 during implantation?

Answer 3

Called the window of implantation
Endometrium becomes receptive to the embryo
Come hither signals - LIF/EGF
Go away signals - Muc1

Question 4

What happens around day 10 of implantation?

Answer 4

Trophoblast produce bHCG which causes the maternal recognition of pregnancy
Maintains the corpus luteum due to progesterone production
Decidualisation under progesterone

Question 5

What does the bHCG (human chorionic gonadotrophin) do?

Answer 5

Useful for monitoring early pregnancy complications e.g. Ectopic
Rescues the corpus luteum by causing the continued production of progesterone

Question 6

What are the functions of the placenta?

Answer 6

Steroidogenesis
Nutrition
Removal of waste
Barrier

Question 7

Why is the placenta good at its job?

Answer 7

Huge reserve in function

Highly adapted and efficient transfer system

Question 8

Key steps of building a placenta

Answer 8

Differentiation of the trophoblast
Trophoblastic invasion of the decidua and myometrium
Remodelling of the maternal vasculature in the utero placental circulation
Development of vasculature within the villi

Question 9

What are the functions if the amniotic cavity?

Answer 9

Homeostasis
Vital for development e.g. Limbs and lungs
Protection

Question 10

Disorders of amnion

Answer 10

Polyhydramnios –> too much amniotic fluid

Oligohydramnios –> too little amniotic fluid