Lecture 15

Question 1

What day after fertilisation does cell division occur?

Answer 1

day 2-4

Question 2

What day does the blastocyte reach the uterus?

Answer 2

Day 4-5

Question 3

What day does the blastocyte implant into the uterus?

Answer 3

Day 5-9

Question 4

what are the two types of trophoblast cells that are essential for the placenta?

Answer 4

Syncytiotrophoblasts and cytotrophoblasts

Question 5

What are syncitiotrophoblasts?

Answer 5

Multinucleated, multivillous membrane structure. it is a singular epithelial membrane around the placenta. It secretes hormones and growth factors.

Question 6

What is the cytotrophoblast?

Answer 6

millions of individual cells that lie underneath the syncytial membrane. they are stem cell like

Question 7

what are the two functions of the cytotrophoblasts?

Answer 7

To proliferate and fuse to form the syncytiotrophoblasts and to exit the syncytium and invade the uterine wall to keep them connected.

Question 8

By how much does blood volume increase in pregnancy?

Answer 8

35-50%

Question 9

What changes occur in pregnancy?

Answer 9

Increase in CO, HR, SV. Decrease in TPVR. Increased left ventricular end diastolic volume and left ventricular stroke volume. Left ventricular mass increases.

Question 10

What are the two types of vascular remodelling?

Answer 10

Upstream main uterine arcuate and radial arteries. these are the myogenic resistant arteries. Or in the terminal spiral arteries where blood exits the uterine cavity and enters the placenta.

Question 11

What are the two main vasodilators in arterial remodelling and which seems to be most important?

Answer 11

NO and EDHF, EDHF more important

Question 12

Is there an increased endothelial derived vasodilation reserve in pregnancy?

Answer 12

Yes

Question 13

What opens the spiral arterioles onto the placenta membrane?

Answer 13

EVT. This captures the blood at the placental interface.

Question 14

Which type of remodelling occurs early in pregnancy?

Answer 14

Upstream remodelling due to circulating hCG levels.

Question 15

At what point in pregnancy is spiral arteriole remodelling complete?

Answer 15

12-16 weeks

Question 16

What is the outcome of arteriole remodelling?

Answer 16

Supply of low pressure, low turbulence blood to the intervillous spaces.

Question 17

What are some signs of pre-eclampsia?

Answer 17

New onset hypertension and proteinuria, altered umbilical artery and uterine artery pulsatility. Raised sFlt-1 levels and soluble endoglin. reduced PLGF

Question 18

What do the raised sFlt-1 and endoglin levels do?

Answer 18

They bind to plasma growth factors which prevents them from binding to the receptors so foetal growth factor mediated remodelling of arteries does not occur.

Question 19

What happens to the endothelial derived vasodilation reserve in pre-eclampsia?

Answer 19

Removed.