Embryology -The placenta Flashcards
(84 cards)
what happens at day 7
a.begins inmplantation via integrin connections and HB-EGF
b.amniotic sac starts to form in epiblast layer
c.a yolk sac starts to form (hausers membrane marks outer circymference) and the extraembryonic mesoderm begins to develop (fetal pole - increased cytotrophoblasts compared to opposite side)
d.extraembryonic mesoderm surrounds the amnion and yolk sac with specialised mesoderm surrounding
yolk sac (extraembryonic sphanchnic mesoderm)
amnion (extraembryonic somatic mesoderm)
a.begins inmplantation via integrin connections and HB-EGF
what happens at day 8
a.begins inmplantation via integrin connections and HB-EGF
b.amniotic sac starts to form in epiblast layer
c.a yolk sac starts to form (hausers membrane marks outer circymference) and the extraembryonic mesoderm begins to develop (fetal pole - increased cytotrophoblasts compared to opposite side)
d.extraembryonic mesoderm surrounds the amnion and yolk sac with specialised mesoderm surrounding
yolk sac (extraembryonic sphanchnic mesoderm)
amnion (extraembryonic somatic mesoderm)
b.amniotic sac starts to form in epiblast layer
what happens at day 9
a.begins inmplantation via integrin connections and HB-EGF
b.amniotic sac starts to form in epiblast layer
c.a yolk sac starts to form (hausers membrane marks outer circymference) and the extraembryonic mesoderm begins to develop (fetal pole - increased cytotrophoblasts compared to opposite side)
d.extraembryonic mesoderm surrounds the amnion and yolk sac with specialised mesoderm surrounding
yolk sac (extraembryonic sphanchnic mesoderm)
amnion (extraembryonic somatic mesoderm)
c.a yolk sac starts to form (hausers membrane marks outer circymference) and the extraembryonic mesoderm begins to develop (fetal pole - increased cytotrophoblasts compared to opposite side)
what happens at day 12
a.begins inmplantation via integrin connections and HB-EGF
b.amniotic sac starts to form in epiblast layer
c.a yolk sac starts to form (hausers membrane marks outer circymference) and the extraembryonic mesoderm begins to develop (fetal pole - increased cytotrophoblasts compared to opposite side)
d.extraembryonic mesoderm surrounds the amnion and yolk sac with specialised mesoderm surrounding
yolk sac (extraembryonic sphanchnic mesoderm)
amnion (extraembryonic somatic mesoderm)
d.extraembryonic mesoderm surrounds the amnion and yolk sac with specialised mesoderm surrounding
yolk sac (extraembryonic sphanchnic mesoderm)
amnion (extraembryonic somatic mesoderm)
what do syncitrotropoblast originate from
a.cytotrophoblast
b.extraembryonic coelom
c.trophoblastic lacunae
a.cytotrophoblast
invasive and form placenta anywhere eg ectopic pregnancy if implantation in fallopian tubes
at day 12 what start to form in the syncitotrophoblasts
a.trophoblastic lacunae form
b.amniotic sac starts to form in epiblast layer
c.a yolk sac starts to form (hausers membrane marks outer circymference) and the extraembryonic mesoderm begins to develop (fetal pole - increased cytotrophoblasts compared to opposite side)
a.trophoblastic lacunae form
(primitive vessels)
at day 12 what are encapsulated in the syncitotrophoblast layer fuelling the embryo with nutrients
a. maternal sinusoids
b.trophoblastic lacunae
c. extraembryonic coelom
d.chorionic cavity
a. maternal sinusoids
open and fill trophoblastic lacunae
what starts to appear at day 12 and engulfs the fetal tissue creating the chorionic cavity
a. maternal sinusoids
b.trophoblastic lacunae
c. extraembryonic coelom
d.chorionic cavity
c. extraembryonic coelom
from day 12-16 extra embryonic mesoderm underlying citotrophoblasts is tied via a connecting stalk to the underlying fetus this will become the
a.placenta
b.umbilical cord
c.chorionic cavity
b.umbilical cord
the chorion is known as the rudimentary placenta what does it consist of
a. extraembryonic mesoderm, citotrophoblasts , syncitiotrophoblasts
b.chorionic cavity, extraembryonic mesoderm, citotrophoblasts
c.extraembryonic mesoderm, amniptic cavity, extra embryonic coelom
a. extraembryonic mesoderm, citotrophoblasts , syncitiotrophoblasts
at what point do primary chorionic villi begin to fill with mesoderm to become seondary chorionic villi
a. week 1
b. week 2
c. week 3
d.week 4
c. week 3
at week 3 what structures expand and become continuous with the maternal blood vessels and endometrial glands to establish a feto maternal exchange
a. maternal sinusoids
b.trophoblastic lacunae
c. extraembryonic mesoderm
b.trophoblastic lacunae
what best describes the structure of a primary villi
a.cytotrophoblasts core, with a surrounding layer of syncitiotrophoblasts
b. mesoderm core with surrounding layer of cytotrophoblasts and a layer of syncitiotrophoblasts surrounding this
c. mesoderm differentiates to form small blood vessels and fetal blood
a.cytotrophoblasts core, with a surrounding layer of syncitiotrophoblasts
what best describes the structure of a secondary villi
a.cytotrophoblasts core, with a surrounding layer of syncitiotrophoblasts
b. mesoderm core with surrounding layer of cytotrophoblasts and a layer of syncitiotrophoblasts surrounding this
c. mesoderm differentiates to form small blood vessels and fetal blood
b. mesoderm core with surrounding layer of cytotrophoblasts and a layer of syncitiotrophoblasts surrounding this
what best describes the structure of a tertiary villi
a.cytotrophoblasts core, with a surrounding layer of syncitiotrophoblasts
b. mesoderm core with surrounding layer of cytotrophoblasts and a layer of syncitiotrophoblasts surrounding this
c. mesoderm core with fetal capillaries and a reduction in the number of cytotrophoblasts
c. mesoderm core with fetal capillaries and a reduction in the number of cytotrophoblasts
c. mesoderm differentiates to form small blood vessels and fetal blood
week 3 summary
connection between fetal and maternal blood vessels
growth of rudimentary placenta > faster than that of fetus
chorionic cavity surrounds fetal tissues but remains connected via extraemesoderm conneting stalk
villi more mature secondary villi at embryonic pole
chorion (primitive placenta) made up of estramesoderm, citotrophoblasts, syncitiotrophoblasts (invade maternal endometrium opening maternal sinusoids so blood flows into trophoblastic lacunae)
cytotrophoblasts begin to proliferate around synciotrophoblasts in collars
when do tertiary villi form
a,week 2
b.week 3
c.week 4
d.week 5
d.week 5
at what point will the cytotrophoblasts have fully encompassed the syncitiotrophoblasts creating the cytotrophoblast shell
a,week 2
b.week 3
c.week 4
d.week 5
d.week 5
an bv infiltrate into core of tertiary villi
centre of interveilliois space - maternal sinusoids
directly surrounding- syncitiotrophoblasts (line the intervillous space)
then - cytotrophoblasts
then - extraembryonic mesoderm (villus)
at what point does the connecting stalk mesoderm start to develop fetal capillaries as well as creating the primitive umbilical cord
a,week 2
b.week 3
c.week 4
d.week 5
which arterise do the cytotrophoblasts invade in the endometrium to create hybrid vessels
a. spiral
b.sinusoidal
c.lacunae
a. spiral
altered and now contain cytotrophoblasts in wall
what are the intervilllous spaces coated by?
a.syncitiotrophoblasts
b.citotrophoblasts
c. mesoderm
a.syncitiotrophoblasts
which cells invade the spiral arteries and replace part of their wall
a.syncitiotrophoblasts
b.citotrophoblasts
c. mesoderm
b.citotrophoblasts
dilates arteries to pool blood into intervillous spaces
addition of cititrophoblasts has what effect on spiral artery diametre
a.increase
b.decrease
a.increase
addition of cititrophoblasts has what effect on spiral artery vascular resitance
a.increase
b.decrease
b.decrease
pressure of blood through intervillous space LOW so no pressure on fetal blood stream