Growth Restriction

Question 1

Describe placental development

Answer 1

Begins at the implantation of the blastocyst
This thins out and becomes the trophoblast –start of the placenta

Syncytiotrophoblast invades decidua (endometrium)
Cytotrophoblast cells erodes maternal spiral arteries and veins
Spaces (lacunae) between the fill up with maternal blood
Followed by mesoderm that develops into fetal vessels
Aiding the transfer of nutrients, O2, across a simple cellular barrier

Question 2

Cytotrophoblast cells (CTB)

Answer 2

Undifferentiated stem cells
Invade the maternal blood vessels and destroy the epithelium
Give rise to the syncytiotrophoblast cells (STB)
Reduce in number as pregnancy advances

Question 3

Syncytiotrophoblast cells (STB)

Answer 3

Fully differentiated cells
Direct contact with maternal blood
Produce placental hormones

Question 4

Name 2 hormones released by the placenta

Answer 4

HCG

HPL

Question 5

Human chorionic gonadotrophin (HCG)

Answer 5

produced by placenta after implantation- detected in pregnancy tests

maintenance of corpus luteum of pregnancy

production of progesterone and oestrogen

Question 6

Human placental lactogen HPL

Answer 6

embryonic development, growth, lactation

Question 7

As the pregnancy progresses what happens to cytotrophoblasts

Answer 7

decrease

Question 8

Describe the placental barrier

Answer 8

Monolayer of syncytiotrophoblast/cytotrophoblast/fetal capillary epithelium is all tha seperates the fetal and maternal blood

this barrier thins as the pregnacy advances which lead to a greater surface area for exchange

Question 9

When does transfer of the maternal antibodies IgF occur

Answer 9

12 weeks (however most others at 34wks)