Anatomy of the placenta lecture Flashcards
what is the placenta
complex temporary structure expressed during the third stage of labour
dualistic origin derived form both the mother and foetus
connection through umbilical cord, maternal and fetal blood do not mix
protects embryo and foetus exchange
fetal part of placenta
develops form chorion fondosum
maternal side of placenta
decidua basalis
which hormones does the placenta secrete
oestrogen and progesterone
gross anatomy of the mature placenta
flattened discoid organ
20cm diameter
2.5 cm thick at centre and thins out towards circumference
450-500g
fetal surface covered with amnion 9inner membrane)umbilical cord inserted
maternal surface B attached to decide, formed by approx 15-20 cotyledons separated by sulci
gross anatomy of mature membrane
basal and chorionic plates meet at edges
forms chorioamnion membranes where amniotic flus is contained
what is the chorioamnion composed of
chorion (outer)
amnion (inner)
what is the chorion derived from
trophoblast layer of blastocysts cells
opaque
amnion
translucent
connective tissue base
non-iliarted epithelial cells
gross anatomy of mature umbilical cord or funds
extends from fetal surface of placenta to umbilical areas of foetus
originates from duct between amniotic sac and rock sac
2 umbilical arteries which spiral around 1 umbilical vein in Whartons Jellu
what is Whartons jelly
mucoid connective tissue
what is in the image and label
umbilical cord
implantation
where is the placenta formed from
outer cell mass differentiating to trophoblast
forming placenta and membranes
extravillous trophoblasts of first trimester
highly invasive
form cell columns that extend from endometrium to the inner third of the myometrium
2 stages of placenta formation
prelacunar
lacunar
prelacunar
day 7
blastocyst makes contact with the decider and placentation begins
lacunar
formation for lacunae which will become intervillous spaces
filled with maternal blood- basal plate
what does the trophoblast lineage give rise to in the human placenta
syncytiotrophoblast
villous cut-trophoblast
extravillous trophoblast
what does the syncytiotrophoblast form
forms epithelial covering of the villous tree
main endocrine component of the placenta
waht does the villous cytotrophoblast form
represents germinative population that proliferate throughout pregnancy and fuse to generate the syncytiotrophoblast
extravillous trophoblast cells
non-proliferative
invade the maternal endometrium
cell shape of cytotrophoblast cells that form the mural and polar trophoblast
cuboidal
covered externally with syncytial trophoblast
label the image
label the image
what does the chorionic plate consist of
Primitive mesenchymal tissue containing branches of umbilical vessels
Layer of cytotrophoblast & Syncytiotrophoblast
Stem villi connected to chorionic plate
what does the basal plate consist of
Part of layer of decidua basalis
Degeneration of the outer Syncytiotrophoblast at the cytotrophoblast shell & decidua junction
Cytotrophoblast shell
Syncytiotrophoblast
acts as a reservoir for blood
vasculature of the basal plate
spinal branches of the uterine vessels through which maternal blood flows into intervillous space
what does the septum consist of
decimal elements covered by trophoblastic cells
areas between septa
cotyledons
seen on maternal surface
physiology of maternal placental circulation
label the image of the placental villi
short cord
traction and premature separation leading to insufficiency
abruption
long cord
cord around neck
cord prolapse
true knot
hyper and hypo-coiled cord
intrauterine growth restriction, fetal demise, associated with hypertensive disorders, placental abruption, maternal diabetes, polyhydramnios
anomalous insertions of the cord
marginal/Battledore, velamentous bifurcate – retained placenta, vasa previa, fetal blood loss - anaemia
vasa previa
anaemia, fetal demise
incorrect placenta implantation
early miscarriage
abnormal trophoblast invasion
placenta accreta, pre eclampsia, infarctions, abruption, pre-eclampsia,
low lying placenta and placenta previa
lower segment caesarean section, Short cord- traction and premature separation leading to insufficiency- abruption
Bi lobed/Succenturiate lobe placenta
vasa previa, post-partum hemorrhage and infection