Lecture 15 Flashcards
What day after fertilisation does cell division occur?
day 2-4
What day does the blastocyte reach the uterus?
Day 4-5
What day does the blastocyte implant into the uterus?
Day 5-9
what are the two types of trophoblast cells that are essential for the placenta?
Syncytiotrophoblasts and cytotrophoblasts
What are syncitiotrophoblasts?
Multinucleated, multivillous membrane structure. it is a singular epithelial membrane around the placenta. It secretes hormones and growth factors.
What is the cytotrophoblast?
millions of individual cells that lie underneath the syncytial membrane. they are stem cell like
what are the two functions of the cytotrophoblasts?
To proliferate and fuse to form the syncytiotrophoblasts and to exit the syncytium and invade the uterine wall to keep them connected.
By how much does blood volume increase in pregnancy?
35-50%
What changes occur in pregnancy?
Increase in CO, HR, SV. Decrease in TPVR. Increased left ventricular end diastolic volume and left ventricular stroke volume. Left ventricular mass increases.
What are the two types of vascular remodelling?
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.
What are the two main vasodilators in arterial remodelling and which seems to be most important?
NO and EDHF, EDHF more important
Is there an increased endothelial derived vasodilation reserve in pregnancy?
Yes
What opens the spiral arterioles onto the placenta membrane?
EVT. This captures the blood at the placental interface.
Which type of remodelling occurs early in pregnancy?
Upstream remodelling due to circulating hCG levels.
At what point in pregnancy is spiral arteriole remodelling complete?
12-16 weeks
What is the outcome of arteriole remodelling?
Supply of low pressure, low turbulence blood to the intervillous spaces.
What are some signs of pre-eclampsia?
New onset hypertension and proteinuria, altered umbilical artery and uterine artery pulsatility. Raised sFlt-1 levels and soluble endoglin. reduced PLGF
What do the raised sFlt-1 and endoglin levels do?
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.
What happens to the endothelial derived vasodilation reserve in pre-eclampsia?
Removed.
