Lecture 13: Extraembryonic Tissues & Placenta Flashcards

0
Q

What are the amnion and yolk sac derivatives of?

A

Amnion: epiblast

Yolk sac: hypoblast

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1
Q

Name the extraembryonic tissues.

A

Amnion, Yolk sac, Chorion, & Allantoes

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2
Q

What do the chorion and allantois interface with?

A

Chorion: part of fetal maternal interface
Allantois: placenta via umbilical cord

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3
Q

What two things make up the fetal-maternal interface?

A

Placenta and Chorion

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4
Q

What are functions of the amnion?

A

Buffer against mechanical injury, Accommodate growth, Allow normal movements, & protect fetus from adhesions

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5
Q

High levels of alpha-fetoprotein are strong indicators of _____.

A

Neural tube defects

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6
Q

Creatinine or Lecithin-to-sphingomyelin ration can be used to determine what?

A

Fetal maturity based on maturity of lungs

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7
Q

What is hydramnios frequently associated with?

A

Esophageal atresia or anencephaly

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8
Q

What is oligohydramnios frequently associated with?

A

Renal agenesis

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9
Q

What occurs during phase I of amniotic fluid formation?

A

Diffusion of electrolytes through fetal ectoderm, maternal serum added, secretion by amniotic membrane

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10
Q

What occurs during phase II of amniotic fluid formation?

A

Fetal urine added & filtration for vessels associated with chorion leave

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11
Q

What is the turnover rate of amniotic fluid in the 3rd trimester and at term?

A

3rd trimester: every 3 hours

Term: 500 mL/hour

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12
Q

Folic acid and vitamins A, B12, and E may concentrate where?

A

Yolk sac

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13
Q

Where is the site of origin of primordial germ cells and the location of blood islands?

A

Yolk sac

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14
Q

What is histiotrophic nutrition?

A

Endocytosis of folic acid and vitamins A, B12, & E in the yolk sac

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15
Q

What is Meckel’s Diverticulum?

A

a remnant of the yolk duct that appears as a fibrous cord or out-pouch of the small intestine

16
Q

Where do allantoic vessels form?

A

Mesoderm of allantois

17
Q

The proximal part of the allantois is also known as _____ and associated with formation of the _____. It then becomes the _____.

A

Urachus.
Urinary bladder.
Median umbilical ligament

18
Q

In the previllous embryo _____ villi have formed on the trophoblast.

A

No

19
Q

In the primary villi stage _____, _____, _____primary villi appear.

A

Solid, cytotrophoblastic, ectodermal

20
Q

In the secondary villous stage, _____ appear within the primary villi.

A

Mesodermal cores

21
Q

In the tertiary villous stage _____ appear in the mesenchymal core of the secondary villi.

A

Blood vessels

22
Q

What are hofbauer cells?

A

Fetal macrophages

23
Q

What do cytotrophoblastic columns do?

A

Hold placenta in place

24
Q

What is the chorionic plate VS the cytotrophoblastic shell?

A

Chorionic plate: fetal side.

Cytotrophoblastic shell: covers maternal decidual shells on maternal side

25
Q

Which genes are expressed while the placental villi are being established?

A

Msx2 & Dlx4

26
Q

The exit from the cell cycle at points of branching on villi is due to what?

A

Transcription factor Gem-1

27
Q

What are the layers from amnion to outer cytotrophoblastic shell?

A

Amion–>Chorionic cavity–>Chorionic plate–>Villi–>Syncytiotrophoblast–>Outer cytotrophoblastic shell

28
Q

What is the chorionic leavae?

A

Area where villi go away because they’re not being used

29
Q

What is the pathway of maternal blood flow?

A

Enters trophoblastic lacunae–>exchange of materials with fetal blood in capillaries–>Exits maternal veins in decidua basalis

30
Q

What is the pathway of fetal blood flow?

A

Enters capillary beds in villi via umbilical arteries–>Exchange of materials with maternal blood–>Exits capillary bed via umbilical vein