Embryology -The placenta Flashcards
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
At week 5 what is the barrier between fetal and maternal circulation made up of
a.citotrophoblasts
b.syncitiotrophoblasts
b.citotrophoblasts and syncitiotrophoblasts
d.chorionic villi and mesoderm
e.citotrophoblasts and syncitiotrophoblasts , endothelium of fetal bv
e.citotrophoblasts and syncitiotrophoblasts , endothelium of fetal bv
which type of villus extends from extraembryonic mesoderm up to cytotrophoblastic shell
a. stem
b.branch
a. stem
which type of villus allows for exchnage between fetal vessels and intervillus spaces and increases surface area
a. stem
b.branch
b.branch
later in development the barrier in the branched villi is formed by…
a.citotrophoblasts and fetal vessel endothelium
b.syncitiotrophoblasts and endothelium of fetal vessel
c.endometrium and citotophoblasts
b.syncitiotrophoblasts and endothelium of fetal vessel
later in development which villi have a barrier consisting of syncitiotrophoblasts and fetal vessel endothelium only
a.stem
b.branch
b.branch
what is the placenta made up of
a.fetal tissue
b.fetal and maternal tissue
c.maternal tissue
b.fetal and maternal tissue
maternal side exposed to very little fetal blood
in which situation does haemolytic disease result when maternal and fetal blood mix
a.Rh + fetus, Rh-ve mother
b.Rh - fetus, Rh +ve mother
a.Rh + fetus, Rh-ve mother
fetus has Rh antigen ,mother has Rh antibodies sees fetal RBC as foreign (cross placenta)
in which pregnancy is haemolytic generally more of a problem
a. first pregnancy
b.second pregnancy
c.third pregnancy
b.second pregnancy
most antibodies produced from first exposure during labour/ trauma in pregnancy
haemolytic disease in newborns describes destruction of which cell type in the fetus by maternal antibodies
a. rbc
b.wbc
a. rbc
what are the 2 main elements of the placenta
a.chorion fundosum
which part of the placenta is the fetal contribution
a.chorion fundosum
a.chorion fundosum
which part of the placenta is the maternal contribution
a. chorion fundosum
b. decidua
b. decidua
which reaction occurs in CT of endometrium at implantation that prepares the decidua
a.decidual
b.chorionic
a.decidual
progesterone chnages CT to secretory cell type
increased vasc swelling and glycogen granules and oedema of interstitial fluid
increased capilliries in endometrium
the embryonic pole decidua is known as the
a.decidua basalis
b.decidua capsularis
c.decidua parietalis
a.decidua basalis
will become the placenta
which part of the decidua is at the opposite end to the embryonic pole
a.decidua basalis
b.decidua capsularis
c.decidua parietalis
b.decidua capsularis
all of the other endometrial surface not directly associated with the embryo is known as
a.decidua basalis
b.decidua capsularis
c.decidua parietalis
c.decidua parietalis
when do the decidua capsularis and parietalis fuse with the amniochorionic membrane
a.week 3
b.week 5
c. end of trimester 1
d.end of trimester 2
c. end of trimester 1
which two structures fuse with the amniochorionic membrane by the end of the first trimester
a.decidua capsularis and decidua parietalis
b.decidua capsularis and decidua basalis
c.decidua basalis and decidua parietalis
a.decidua capsularis and decidua parietalis
surounds baby - amniotic sac
which structure becomes the maternal portion of the placenta and is discoid in shape
a.decidua basalis
b.decidua capsularis
c.decidua parietalis
a.decidua basalis
joined with chorionic plate on fetal side
the chorionic plate on the fetal side of the placenta is completely covered by what
a.chorion frondosum
b.amnion
b.amnion
the maternal side of the placenta (formed form the decidua basalis) is seperated into regions known as…
a.lobules
b.cotyledons
c.chorion
d.amnion
b.cotyledons
contain 2 or more stem villi
cotyledons are separated by maternal septa which house
a.maternal vessels
b.fetal vessels
a.maternal vessels
placental hormones are mainly secreted by the
a.cytotrophoblast
b.syncitiotrophoblast
c.lacunae
b.syncitiotrophoblast
eg HCG detectable at day 8
which hormone is most responsible for morning sickness
a.hcg
b.pth
c.oestrogen
d.progesterone
a.hcg
stops at 4 weeks
maintains corpus luteum
progesterone levels from placenta in pregnancy
a.rise
b.fall
a.rise
then corpus luteum produces it
progesterone inhibits contraction of myometrium
which hormone prevents contraction of the uterine myometrium and maintaining the endometrium, as well as increasing the proliferation of mammary endothelium
a.hcg
b.progesterone
c.oestrogen
d. relaxin
b.progesterone
which hormones promote angiogenesis and vasodilation and maintain uterine lining
a.hcg
b.progesterone
c.oestrogen
d. relaxin
e.placental lactogen
c.oestrogen
which hormones promote angiogenesis and vasodilation and maintain uterine lining
a.hcg
b.progesterone
c.oestrogen
d. relaxin
e.placental lactogen
c.oestrogen
which hormone regulates maternal lipid and carb metabolism
a.hcg
b.progesterone
c.oestrogen
d. relaxin
e.placental lactogen
e.placental lactogen
which hormone softens the cervix, and weakens the pubic symphysis
a.hcg
b.progesterone
c.oestrogen
d. relaxin
e.placental lactogen
d. relaxin
which hormone only appears in significant amounts at the end of pregnancy with a sharp rise at birth (inducing contractions)
a.hcg
b.progesterone
c.oestrogen
d. oxcytocin
e.placental lactogen
d. oxcytocin
what is contained in the amniotic sac
a.fetus and umbilical cord
b. fetus umbilical cord and placenta
c.fetus
a.fetus and umbilical cord
filled with up to 1L of fluid
water, salt, fetal cells - amniocentesis and geentic tests
what is amniotic fluid made from
a.water
b.maternal interstitial fluid
c.maternal blood
d.maternal CSF
b.maternal interstitial fluid
leaking from maternal endometrium across amniotic membranes
later on in pregnancy what is amniotic fluid made up of
a.maternal interstitial fluid
b.fetal blood
c. maternal interstitial blood and fetal urine
c. maternal interstitial blood and fetal urine
amniotic fluid effect when inhaled and ingested by fetus
hydrates skin, lungs and GI tract
Gi blockages in the fetus has what effect on amniotic fluid volume
a.increase
b.decrease
a.increase
polyhydramnios
oligohydramnios is caused by what?
a.UT obstruction
b. GI blockages
a.UT obstruction
role of amniotic sac
allows free movement of fetal limbs - muscular tone
acts as a cushion
lubricant to protect friction of movement against surrounding membrane
limit temperature fluctuations
normal umbilical cord
50-6- cm
2-3 cm thick
what makes up the umbiical cord
a. 2 arteries 1 vein
b.2 veins one artery
a. 2 arteries 1 vein
what is carried in the umbilical vein
a.oxygenated blood
b.deoxygenated blood
a.oxygenated blood
from placenta to fetus
what is carried in the umbilical artery
a.oxygenated blood
b.deoxygenated blood
b.deoxygenated blood
from fetus to placenta
what is longer
a.umbilical vessels
b.umbilical cord
a.umbilical vessels
encapsulated in whartons jelly
cord spirals left sided
single umbilical artery increases chances of
a.knots and restriction
b. compressions in birth canal
c.prevented flow
d.genetic conditions
d.genetic conditions
which of these umbilical abnormalities refers to the situatio when the umbilical cord being wrapped around the enck of the fetus
a.nucchal cord
b.entanglement
c.prolapse
d.compression
a.nucchal cord
compression of the cord as the baby passes through the canal is known as
a.nucchal cord
b.entanglement
c.prolapse
d.compression
c.prolapse
where does the umbilical cord usually insert into the placenta
a.centre
b.rhs
c.lhs
d.front
e.back
a.centre
marginal insertion refers to
a.umbilical cord insertion to edge of placenta
b.part of umbilical cord remains without protection of whartons jelly
a.umbilical cord insertion to edge of placenta
velamentous insertion refers to
a.umbilical cord insertion to edge of placenta
b.part of umbilical cord remains without protection of whartons jelly
b.part of umbilical cord remains without protection of whartons jelly
prone to compression and rupture
abnormal shape to the placenta is known as
a.marginal insertion
b.velamentous insertion
c.placental previa
c.placental previa
low lying placenta
forms over internal cervical os
formation of the placenta over the internal cervical os leads to
a.marginal insertion
b.velamentous insertion
c.placental previa
c.placental previa
bleeding throughout pregnancy
requires c section in most cases
if previa placenta stays low covering cervix it may block placentas way out this will cause
a.early labour
b.late labour
a.early labour
try to give birth through placenta incompatible with life of mother and baby
c section needed
what is required if placenta previa remains at end of pregnancy
a.c section
b. vaginal delievry
a.c section
which placental condition is characterised by hypertension and protein in the urine after 20 weeks
a. placenta previa
b.cord prolapse
c.nucchal cord
d.pre eclampsia
d.pre eclampsia
which cells are most involved in pre eclmapsia due to abnormal invasion of spiral arteries
a.cytotrophoblasts
b.synciotrophoblasts
a.cytotrophoblasts
dont fully change to hybrids in maternal cells, incomplete remodelling if spiral arteries so lumen small than usual and high pressure
the lumen of spiral arteries is …….. in pre eclampsia
a.wider
b.thinner
b.thinner
low resitance low flow
compensation effort -> hypertension
complications for fetus - restricted growth
mother - eclampsia, seizures, renal failure, pulmonary oedema
morbidly adherant placenta 3 types
accreta
increta
percretia
refer to depth of invasion by chorionic villi
in MAP accreta the chorionic villi penetrate which uterine layer
a.decidua basalis
b.myometrium
c.peritoneum
a.decidua basalis
attaches to myometrium
in placenta accreta the chorionic villi penetrate which uterine layer
a.decidua basalis
b.myometrium
c.peritoneum
b.myometrium
deep in myometrium
in placenta percretia the chorionic villi penetrate which uterine layer
a.decidua basalis
b.myometrium
c.peritoneum
c.peritoneum
attaches to adjacent organs
