Placenta Yan Flashcards
What makes up a blastocyste?
an inner cell mass and outter cell mass (trophoblast)
What happens on day 6 of fertilization?
trophoblast cells of blastocyst invades uterine epithelium
What happens on day 8 of fertilization?
trophoblast splits into 2 layers, the outter synctrophoblast and inner cytotrophoblast
What happens on day 9 of fertilization?
fibrin coaglum develops
trophoblast is in lacunar stage
primitive yolk sac forms
What is the closure of the penetration defect called?
the fibrin coagulum
How do we get to the lacunar stage?
On day 9: vacuole formation-> fusion -> lacunae
What happens on Day 11 and 12 of fertilization?
establishment of uteroplacental circulation
maternal blood enters
How do we get uteroplacental circulation?
trophoblast lacunae-> meet with maternal sinusoids-> maternal blood enters the lacunar system
What happens on day 13 of fertilization?
Primary villi fomration
How do we get primary villi formation?
cytotrophoblastic cells will proliferate and penetrate into synctiotrophoblast which create columns and make villi
How do we get secondary villus formation?
mesodermal cells penetrate the core of 1st villi
How do we get a tertiary villus formation?
mesoderm cells become blood cells and blood vessels
At the end of the third week, what happens?
maternal vessels penetrate cytotrophoblastic shell and enter intervillous space
At the third week, maternal vessels penetrate cytotrophoblastic shell and enter intervillous space. These capillaries in the villi are in contact with what?
with vessels in chorionic plate and connecting stalk which are connected to intraembryonic vessels
At the end of the 3rd week what happens?
the secondary and tertiary vills give the trophoblast a radial shape.
What are the intervillous spaces lined with?
synctium