Placenta and Fetal Membranes Flashcards
What are 4 fetal membranes as shared by Dr. Dennis?
Chorion
Amnion
Umbilicle Vesicles
Allantois
The placenta is a fetomaternal organ with two components. What are those components that are contributed by the fetal part and maternal part?
Fetal part: choronic sac (outermost part of fetal membrane)
Maternal part: decidua basalis
Correctly name the subcomponent layers of the decidua as they are described below.
____: just deep to the conceptus (embryo) and forms the maternal part of the placenta
_____: overlies conceptus
____: part of the uterine wall that’s not directly involved in implantation
Decidua basalis: just deep to the conceptus (embryo) and forms the maternal part of the placenta
Decidua capsularis: overlies conceptus
Decidua parietalis: part of the uterine wall that’s not directly involved in implantation
Which of the following is most likely happening, in regards to implantation, during day 11/12?
A. Blastocyst adheres to the endometrium
B. Trophoblast differentiates into outer synctiotrophoblast and inner cytotrophoblast
C. Synctiotrophoblast erodes blood vessels in the decidua basalis allowing maternal blood to enter lacunar networks
D. primary chorinic villi develop
- A. Blastocyst adheres to the endometrium- day 6*
- B. Trophoblast differentiates into outer synctiotrophoblast and inner cytotrophoblast- day 7*
C. Synctiotrophoblast erodes blood vessels in the decidua basalis allowing maternal blood to enter lacunar networks - day 11/12 marks the establishment of uteroplacental circulation
D. primary chorinic villi develop - day 13/14
T/F: In ectopic pregnancies the blastocysts still produce hCG but at a slower rate than normal pregnancies
True
What makes up the chorionic sac (3 things)?
What structure is the chorionic sac likely derived from?
Extraembryonic somatic mesoderm
Synctiotrophoblast
Cytotrophoblast
Trophoblast/Hypoblast derived?
Which of the following is true of the amnion?
A. Will eventually obliterate the chorionic cavity as it continue to grow
B. Forms epithelial covering of the umbilical cord
C. Responsible for creating anough physical space for the fetus to grow
D. Filled with amniotic fluid
E. All of the above are correct
All of the above are correct
NOTE: floor of sac is derived from epiblast but that’s according to google, just keep it in the back of your mind just in case…unless extraembryonic somatic mesoderm is an option
The amniotic fluid is initially maternally derived from the maternal tissue and interstitial fluid. It is made of inorganic salts, glycophospholipids, steroid hormones and organic compounds like proteins carbs, fats, and enzymes. Dr. Dennis expressed 3 functions of the amniotic fluid, what were they?
Cushion the fetus
Permit fetal movements
Regulate fetal body temperature
Express the difference between hydramnios and oligohydramnios in the following ways:
- causes
- affects
Causes
Hydramnios is too much amniotic fluid caused by CNS defect or blackage in GI system
Oligohydramnios is too little amniotic fluid (<400) and can be caused by maternal high blood pressure or abnormal placenta
Affects/Complications
Hydramnios: maternal abdomina lpain and distension, increased risk of preterm labor
Oligohydramnios: renal ageneis, pulmonary hypoplasia
Just read:
- the decidua capsularis covers the surface of the chorionic sac
- as the embryo enlarges the decidua capsularis will bulge into the uterine cavity
- the capsularis will thin and fuse with the decidua parietalis on the opposite wall and the uterine cavity will become obliterated on this side
- as the capsularis degenerates around week 22-24, the smooth chorion will fuse with the decidua parietalis
- the amniotic sac grows faster than the chorionic sac and will fuse to form the amniochorionic membrane which will fuse with the capsularis and adhere to the parietalis
Look at this picture
The chorionic villi, which come from the chorionic sac, attach to the decidua basalis through what structure where arteries pass through the gaps and enter the intervillous space?
Cytotrophoblastic shell
The appearance of which of the following villi marks the 1st stage of placental development at the end of week 2?
A. Primary villi
B. secondary villi
C. tertiary villi
Primary villi
Which of the following correctly describes smooth villi?
A. primary villi that associate with decidua basalis
B. primary villi that associate with decidua parietalis
C. primary villi that associate decidua capsularis
D. None of the above
primary villi that associate decidua capsularis
look at those smooth caps
Which of the following correctly describes villous chorion?
A. primary villi that associate with decidua basalis
B. primary villi that associate with decidua parietalis
C. primary villi that associate decidua capsularis
D. None of the above
primary villi that associate with decidua basalis
Extensions of cytotrphoblasts through synctiotrophoblasts forms the cytotrophoblastic shell which surrounds the chorionic sac. Then it attaches and erods __________ and creates the intervillous space.
A. decidua basalis
B. decidua capsularis
C. decidua parietalis
decidua basalis
NOTE: the intervillous space is derived from the lacunae that developed in the invading synctiotrophoblast during the second week
The erosion of the decidua produces placenta septa that grow out into the intervillous space and divides the villous chorion into what u-shaped convex areas?
Cotyledons
NOTE: each cotyledon has 2+ main stem villi and multiple branch villi
Which villi is characterized by extraembryonic mesoderm or mesenchyme connective tissue at the core?
A. PRimary villi
B. Secondary villi
C. Tertiary villi
Secondary villi
Secondary villi overpopulate the intervillous space, with no appearance of tertiary villi. You note that the chorion has failed to engage in nutrient exchange and there’s decreased function of the placenta overall. What most likely occured would indicate which of the following?
A. Failure of extraembryonic mesoderm to differentiate into capillaries
B. Overproliferation of extraembryonic mesoderm within secondary villi
C. Oligohydramnios
D. All of the above
A. Failure of extraembryonic mesoderm to differentiate into capillaries
The presence of what differntiates a secondary from tertiary villi?
A. amount of syntiotrophoblast on it’s outer layer
B. amound of cytotrophoblast core
C. presence of capillaries
D. All of the above
presence of capillaries
What becomes significantly reduced after 20 weeks in placental development?
A. cytotrophoblast population
B. connective tissue within the villi
C. capillary endothelium
D. synctiotrophoblast population
cytotrophoblast population
What prducts do NOT cross the placenta (3)? Include examples
- Protein hormones (insulin)
- bacteria
- drugs with amino acid like structures (methyldopa)
What two things form the umbilical cord?
What are the vascular contents of the umbilical cord?
connecting stalk + amnion
2 umbilical aa. (deoxy blood)
1 umbulical v. (o2 rich blood 80%)
Generally name and describe the 2 most common placental anomalies that were shared in lecture
Placenta Previa: placenta implants in lower uterine segment
Placenta accrete: partial or complete absense of decidua
Placenta accrete can lead to failute of placental seperation at birth, or severe post partum hemorrhage. Why does this oocur?
A. smooth villi adheres to decidua capsularis
B. smooth villi adheres to myometrium
C. villous chorion adheres to myometrium
D. villous chorion adheres to decidua basalis
C. villous chorion adheres to myometrium
NOTE: the decidua basalis gets obliterated, so the villous chorion adheres directly to the myometrium
Hydatiform mole is the replacement of normal villi by dilated or hydropic translucent vesicles. There can be partial mole or complete mole. Describe major differences between the two.
Partial mole: capillaries can be seen in villi, fetal tissue can be found, 1 egg 2 sperm –> triploid or tetraploid
Complete mole: all villi are enlarged, no fetal tissue, all DNA is paternal
Gestational choriocarcinoma is highly invasive metastatic tumor that arises from trophoblast cells. Which of the following is a key pathological concept?
A. decreasing hCG with uterine enlargement
B. decreasing hCG with no uterine enlargement
C. increasing hCG with uterine enlargement
D. increasing hCG with no uterine enlargement
increasing hCG with no uterine enlargement
Dizygotic twins (fraternal) develop from two zygotes. There relationship of membranes is dependent on how the blastocysts implant. What is the likely ersult of the blastocysts implanting seperate from each other?
A. 2 fused everything: 2 amnion, 2 chorion, 2 placenta
B. 2 septerate everything: 2 amnion, 2 chorion, 2 placenta
C. 2 amnion, 2 chorion, 2 fused placenta
D. 2 amnion, 2 fused chorion, and 2 fused placenta
B. 2 septerate everything: 2 amnion, 2 chorion, 2 placenta
Dizygotic twins (fraternal) develop from two zygotes. There relationship of membranes is dependent on how the blastocysts implant. What is the likely result of the blastocysts implanting adjacently?
A. 2 fused everything: 2 amnion, 2 chorion, 2 placenta
B. 2 septerate everything: 2 amnion, 2 chorion, 2 placenta
C. 2 amnion, 2 chorion, 2 fused placenta
D. 2 amnion, 2 fused chorion, and 2 fused placenta
D. 2 amnion, 2 fused chorion, and 2 fused placenta
AACP
Monozygotic twins (identical) originate from one zygote. Their membranes in monozygotic twins are dependent upon time of division. At what stage/time did cleavage occur if we see diamniotic and diochorionic twins?
A. 2-8 cell stage (day 1-3)
B. Blastocyst (day 4-8)
C. Implanted (day 9-12)
2-8 cell stage (day 1-3)
Monozygotic twins (identical) originate from one zygote. Their membranes in monozygotic twins are dependent upon time of division. At what stage/time did cleavage occur if we see diamniotic and monochorionic twins?
A. 2-8 cell stage (day 1-3)
B. Blastocyst (day 4-8)
C. Implanted (day 9-12)
Blastocyst (day 4-8)
Monozygotic twins (identical) originate from one zygote. Their membranes in monozygotic twins are dependent upon time of division. At what stage/time did cleavage occur if we see monoamniotic and monochorionic twins?
A. 2-8 cell stage (day 1-3)
B. Blastocyst (day 4-8)
C. Implanted (day 9-12)
Implanted (day 9-12)
NOTE: the earlier the split, the more seperate the membranes and placentas will be
