Fetal membranes, placenta, and multiple pregnancies Flashcards
Which 3 components make up blastocyst?
Trophoblast, inner cell mass, and blastocyst cavity
Which two components make up trophoblast?
syncytiotrophoblast and cytotrophoblast
When do lacunae appear in syncytiotrophoblast?
Day 10
When do lacunar networks form?
Day 12
EEM splits to form
extraembryonic coelom (chorionic cavity)
Extraembryonic somatic mesoderm lines
trophoblast and amnion
Extraembryonic splanchnic mesoderm surrounds
yolk sac
Amniotic membrane is made up of
amniotic epithelium and extraembryonic mesoderm
Chorionic membrane is made up of
extraembryonic mesoderm, cytotrophoblast, syncytiotrophoblast
Yolk sac is made up of
endoderm, extraembryonic mesoderm
The amnion contains amniotic fluid which is produced by
amniotic ectoderm, fetal respiratory tract, and fetal urine
Amniotic fluid is removed by
diffusion and swallowing by the fetus
What are the functions of the amnion?
cushions and protects, prevents adhesions, freedom of movement, controls body temp
Oligohydramnios
Disorder of amniotic fluid resulting in decreased amniotic fluid volume. Results in poor development of the lung tissue and can lead to fetal death. It can be caused by a rupture of the membranes or fetal kidney issues.
Polyhydramnios
Disorder where there is too much amniotic fluid around the baby during pregnancy. Could indicate that the fetus is having trouble swallowing or there is a GI blockage.
Primary villus
contains core of cytotrophoblast
Secondary villus
contains core of mesenchyme
cytotrophoblastic shell
cytotrophoblast extensions that anchor the chorionic sac to endometrium
Tertiary villus
contains fetal capillaries
Which type of circulation predates feto-placental circulation
utero-placental circulation
When does feto-placental circulation develop
21 days
Feto-placental circulation
embryonic blood vessels differentiate from mesenchyme in villi and connecting stalk
chorion leavae
Smooth surface of chorion - forms protective shell around developing fetus
chorion frondosum
rough surface of chorion - portion of chorion that has been modified to increase surface area contact with maternal tissues for physiologic exchange.
What is the allantois
extension of yolk sac into connecting stalk
What does the allantois do
gives rise to umbilical vessels, forms the urachus and median umbilical ligament
What are the three decidua
decidua capsularis, decidua parietalis, decidua basalis
What happens to the decidua capsularis
degenerates
what happens to the decidua parietalis
fuses with chorion
what happens to decidua basalis (smooth chorion)
fuses with amnion
what is the fetal component of the placenta?
chorion frondosum (villous chorion)
what is the maternal component of the placenta?
decidua basalis
What is the chorionic plate in relation to the placenta?
fetal surface of placenta
Which structures make up the full term placenta?
Cytotrophoblastic shell, mainstem villus (trunk), free floating villi, anchoring villi, and branch villi
What does the branch villus do?
Exchange between fetal and maternal blood
Which hormones does the placenta release?
steriod hormones (estrogen and progesterone), prostaglandins, protein hormones
what are the protein hormones
human chorionic gonadotropin, human placental lactogen, human chorionic thyrotropin, human chorionic corticotropin
Contents of intervillous space normally include
oxygen, carbon dioxide, maternal blood, and electrolytes
The amniotic cavity appears on the 8th day of development as a slitlike space between the trophoblast and the
inner cell mass
