PLACENTA Flashcards
how is placenta form
when maternal blood supply. has been accessed
what happens when synctiotrophoblastts invade maternal blood vessels
lacunae form
chorionic villi form
- proliferation of cytotrophoblast
- growth of chorionic mesoderm
- ## blood vessel development
what happens to primary chorionic villi around day 13 post fertilisation
cords or asses of cytotrophoblasts growing into lacunae within synctiotrophoblass
what day is secondary chorionic villi
- days 16
when is teritary chorionic villi
end of third week development
nam
tertiary villi early
name
tertiary villi mature
maternal component of placenta - decidualisatin
after implanation of blastocyst
stroma cells become large round decidual cells
regions of decidua
- decidua basalis
- decidua capsularis
- decidua parietalis
what happens by the end of 3 month for placenta decidualisation
gestation
decidua capsularises fuses with decidua parietalis of opposite wall
which layers of the endometrium form decidua
all but the deepest layer
what does decidua shed with
placenta at birth
what is a cytotrophoblastic shell
complete shell around synctiotrophoblast - attaches to endometrium
what do maternal blood vessels communicate with
through shell
what happens to the villi during pregnancy
mature - smaller in diameter
what happens to the cytotrophoblast during pregnancy
discontinues
plates in mature placenta
basal plate
chorionic plate
what does basal form from in mature placenta
decidual basalis
what does chorionic plate form from in mature placenta
embryological origin
what is the blood supply to the placenta
spiral arteries
what is the placental barrier
seperation of maternal and fetal blood
describe the diameter of the placental barrier
very thin by 4 months > allow exchange of products across placenta
functions of placenta
- metabolism
- transport
- barrier function
- immunological function
- endocrine function
when does placenta take over from
corpus leutrum 8 weeks gestation
what does adrenal cortex provide
androgens
when is human chorionc gonadotropins produced from
6 days post fertilisatin
maintains corpus leutrum < maintains endometrium > and pregnancy
placental problems
- placenta previa
- placenta abruption
what is placenta previa
covers internal os of cervix
what is placenta abruption
comes away from uterine wall
what is pre-eclampsia
pregnancy induced hypertension + protenuria
what is the treatment of pre-eclampsia
delivery of placenta
what is the cause of pre-eclampsia
unknown cause - probkems with endometrial blood vessel problem
what cell secretes HCG
trophoblast cells
which of the cells in the endometrium are mitoticaly active
cytotrophoblast
what fuses with synctiotrophoblasts
cytotrophoblasts
what is not mitotically active
synctiotrophoblasts
what invades into maternal blood vessels
synctiotrophoblasts
what happens after synctiotrophoblasts invade into maternal blood vessels
lacunae form
what happens at the Day 11-12 development
closing plug formed
implanted embryo within wall of endometrium
list the types of villi
primary secondary and tertiary
when does primary chorionic villi occur
around D13 post fertilisation
what happens at the primary chorionic villi
two distinct layers of synctiotrophoblasts and one layer of cytotrophoblasts
when is secondary chorionic villi formed
D16
list the prominent layers of secondary chorionic villi
inner layer cytotrophoblast
outer layer synctiotrophoblast
what is primary villi invaded by
loose ct from chorion
when is tertiary chorionic villi formed
end of 3rd week development
when do blood vessels grow in villi
secondary and tertiary chorionic villi
what can you see in mature tertiary villi
synctial knots
what is the maternal component of placenta
decidualisation
when does decidualisation occur
after implantation of blastocyst (8-10 days of embryo development)
what happens to the stroma cells in decidualisation
they become large round decidual cells
list the regions of decidua
- decidua basalis
- decidua capsularis
- deciduda parietalis
where is decidua capsularis located
between implantation site and lumen
where is decidua parietalis
remaining endometrium
when does decidualisation happen
by end 3rd month gestation
what happens by end of 3rd month gestation in decidualisation
decidua capsularis fuses with deciduda parietalis of opposite wall
what happens when decidua capsularises fuses with dec. parietalis
obliteration of uterine cavity
what shed with placenta at birth
decidua
what shell attaches to endometrium
cytotrophoblastic shell
how do maternal blood vessels communicate
through shell of cytotrophoblastic shell
is growth of villi continuous throughout pregnancy
yes
where do stem villi or anchoring villi grow
into maternal side of placenta > basal plate
what is the size of villi during pregnancy
mature, smaller in diameter
what discontinues during pregnancy
cytotrophoblast
how are synctial knots formed
synctiotrophoblast nuclei gathered in clusters
list the features of mature placenta
basal plate > from decidual basalis
chorionic plate
cotyledons
what divides fetal part of placenta
cotyledons - 15-25
blood supply to placenta
spiral arteries
what does the placental barrier seperate
materal and foetal blood
what is the thickness or thinness of placental barrier
very thin by four months
function of the thinness of placental barrier by 4 months
allows exchange of products across placenta
what does placenta take over from
corpus luteum 8 weeks gestation
when are human chorionic gonadotrophins produced from
day 6 post fertilisation
what does the human chorionic gonadotrophins maintains
corpus luteum
endoemtrium
pregnancy
what is human chorionic gonadotrophins secreted b y
synctiotrophoblasts
what is relaxin from
decidual cells
what does relaxin do
softening of cervix and pelvic ligaments
what are the other hormones secreted by placenta
IGF-1 IGF-II
endothelial growth factors
leptin
treatment of pre-eclampsia
delivery of placenta
what secretes hcg
trophoblastic shell
