Yan: Placenta Flashcards
In the blastocyst, what is the inner cell mass called? The outer cell mass?
embryoblast; trophoblast
What happens on day 6?
invasion of the uterine epithelium by trophoblast cells of the blastocyst
What happens on day 8?
trophoblast forms 2 layers: cytotrophoblast and syncytiotrophoblast
What happens on day 9?
trophoblast enters lacunar stage –> vacuoles form and fuse to form lacunae
formation of primitive yolk sac
On what day is uteroplacental circulation established?
Day 11 and 12
Formation of uteroplacental circulation: trophoblastic lacunae and (blank) integrate and (blank) enters the lacunar system
maternal sinusoids; maternal blood
On day 13, what forms?
primary villi
How do primary villi form?
cytotrophoblastic cell proliferation and penetration into syncytiotrophoblast –> cellular columns –> villi formation
What two things make up the primary villus?
cytotrophoblastic core + syncytial layer
What happens to a primary villus to make it a secondary villus?
mesodermal cells penetrate the core of the primary villi
What happens to a secondary villus to make a definitive villus?
blood vessels derive from mesoderm cells in definitive villi
At the end of 3rd week, maternal vessels penetrate the (blank) shell to enter (blank) spaces, which surround the villi. Capillaries in the (blank) are in contact with vessels in the chorionic plate and the connecting stalk, which in turn are connected to intraembryonic vessels.
cytotrophoblastic; intervillous; villi
Intervillous spaces of the blood contain (blank) blood, while (blank) blood is contained in the villi.
maternal; fetal
At the end of 3rd week, 3rd and 2nd villi give the trophoblast a radial shape. Intervillous spaces are lined with (blank). Cytotrophoblastic cells surround the entire trophoblast and in contact with endometrium. The embryo is suspended in the chorionic cavity by the (blank).
syncytium; connecting stalk
In the fourth week, there is a 4 layer barrier between maternal and fetal blood. What are the layers?
- syncytium
- cytotrophoblast
- CT
- endothelium
By the fourth month, there are only two layers - what are they? Blood vessels move and make contact with the synctiotrophoblast cells.
- syncytium
2. endothelium
By end of (blank) month, villi have disappeared at the abembryonic pole, forming chorion laeve
2nd
By end of the (blank) month, the amnion and chorion have fused and the uterine cavity is obliterated by fusion of the chorion laeve and decidua parietalis.
3rd
T/F: Full-term placenta is shed off uterine wall in 30 mins after child birth.
True
There is a separation between fetal and maternal circulation during placental development, because the fetal circulation is confined within the (blank) and maternal blood confined to (blank).
villi; intervillus space
Function of the placenta
exchange of gases
exchange of nutrients and electrolytes
transmission of maternal antibodies (gain of passive immunity)
hormone production
During pregnancy, the (blank) provides the main source of hormones – there is a duel supply initially from the corpus luteum and the placenta. When placental nutrition is efficient, corpus luteum will degenerate.
placenta
Hormones produced by the placenta and in what part are they produced?
progesterone estrogens hCG somatomammotropin produced in the syncytiotrophoblast
On what day is the fibrin coagulum formed up to close the penetration defect?
Day 9
On what day is the primitive yolk sac formed?
Day 9
