Placenta (Practical)

Question 1

What is the life-time of the yolk sac?

Answer 1

11-20 weeks gestation

Question 2

What is the name of the chorion that is fully covered in villi?

Answer 2

Chorion frondosum

Question 3

What is the name of the chorion over abembryonic pole where the villi regresses?

Answer 3

Chorion leave

Question 4

What is velamenous insertion of the umbilical cord?

Answer 4

Inserion of the umbilical cord into the chorio-amnionic membranes instead of placenta, with vessels then travelling to placenta between amnion and chorion.

Question 5

What are monochorionic diamniotic twins?

Answer 5

• When twin separation occurs in blastocyst stage resulting in development of 2 amnions in one chorion.
• The twins share 2 placentae but 1 chorionic sac.

Question 6

What are monochorionic monoamiotic twins?

Answer 6

• When twin spearation occurs during gastruation, resulting in formation of 2 embryos that share the same amnion and chorion.
• The twins share the same placenta.