Physiology of Placenta Formation

Question 1

what does progesterone cause?

Answer 1

• thickens the lining of endometrium
• endometrium –> decidua
• increase in vascularity

Question 2

what is the chorion?

Answer 2

the egg

Question 3

what lines the outer edge of the chorion?

Answer 3

trophoblast cells

Question 4

what do trophoblast cells produce?

Answer 4

B-HCG

Question 5

what is the function of B-HCG?

Answer 5

• stimulates ovary to continue secreting progesterone throughout pregnancy
• stops decidua from shedding

Question 6

outline what happens once the fertilised egg burrows into the decidua

Answer 6

• trophoblast cells go off to invade mother’s blood vessels to link these up with foetus
• projections of chorionic villi lined with trophoblasts start to move in towards the decidua
• eventually join together and form placenta