Placenta Yan Flashcards

1
Q

What makes up a blastocyste?

A

an inner cell mass and outter cell mass (trophoblast)

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2
Q

What happens on day 6 of fertilization?

A

trophoblast cells of blastocyst invades uterine epithelium

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3
Q

What happens on day 8 of fertilization?

A

trophoblast splits into 2 layers, the outter synctrophoblast and inner cytotrophoblast

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4
Q

What happens on day 9 of fertilization?

A

fibrin coaglum develops
trophoblast is in lacunar stage
primitive yolk sac forms

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5
Q

What is the closure of the penetration defect called?

A

the fibrin coagulum

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6
Q

How do we get to the lacunar stage?

A

On day 9: vacuole formation-> fusion -> lacunae

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7
Q

What happens on Day 11 and 12 of fertilization?

A

establishment of uteroplacental circulation

maternal blood enters

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8
Q

How do we get uteroplacental circulation?

A

trophoblast lacunae-> meet with maternal sinusoids-> maternal blood enters the lacunar system

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9
Q

What happens on day 13 of fertilization?

A

Primary villi fomration

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10
Q

How do we get primary villi formation?

A

cytotrophoblastic cells will proliferate and penetrate into synctiotrophoblast which create columns and make villi

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11
Q

How do we get secondary villus formation?

A

mesodermal cells penetrate the core of 1st villi

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12
Q

How do we get a tertiary villus formation?

A

mesoderm cells become blood cells and blood vessels

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13
Q

At the end of the third week, what happens?

A

maternal vessels penetrate cytotrophoblastic shell and enter intervillous space

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14
Q

At the third week, maternal vessels penetrate cytotrophoblastic shell and enter intervillous space. These capillaries in the villi are in contact with what?

A

with vessels in chorionic plate and connecting stalk which are connected to intraembryonic vessels

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15
Q

At the end of the 3rd week what happens?

A

the secondary and tertiary vills give the trophoblast a radial shape.

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16
Q

What are the intervillous spaces lined with?

A

synctium

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17
Q

At the end of the the third week, (blank) surround the entire trophoblast and are in contact with the endometrium.

A

cytotrophoblastic cells

18
Q

The embryo is suspended in the chorionic cavity by the (blank)

A

connecting stalk

19
Q

What makes up the placental membrane of the placenta in the fourth week?

A

synctium
cytotrophoblast
CT
endothelium

20
Q

What makes up the placental membrane of the placenta in the fourth month?

A

synctium

endothelium

21
Q

By the end of the 2nd month, what disappears and where?

A

villi at the abembryonic pole forming chorion laeve

22
Q

By the end of the 3rd month, what happens?

A

amnion and chorion fuse

uterine cavity is obliterated

23
Q

How does the uterine cavity become obliterated in the third month?

A

by the fusion of chorion laeve and deciuda parietalis

24
Q

How big is a full-term placenta?

A

15-25 cm diameter, 3 cm thick, 500-600g

25
Q

How long does it take for the placenta to shed off the uterine wall after birth of child?

A

30 minutes

26
Q

What are the components to the fetal side of a full-term placenta?

A

amnion, umbilical cord, chorionic plate, chorion vessels

27
Q

What are the components to the maternal side of a full-term placenta?

A

cotyldon and decidua basalis

28
Q

How do you get dizygotic twins?

A

you ovulate 2 eggs at the same time

29
Q

How do you get monozygotic twins?

A

one egg splits into 2

30
Q

What are the 2 kinds of possible dizygotic twin?

A

separate placenta and chorion

fusion of placenta and chorion

31
Q

What are the 3 kinds of possible monozygotic twins?

A

separate placenta and chorion
common placenta
common amniotic cavity

32
Q

How do you get monozygotic twins with a common placenta?

A

you get dont get separate chorions

33
Q

How do you get monozygotic twins with a common amniotic cavity?

A

the amniotic cavities are fused and do not separate

34
Q

How often do you get twin conceptions?

Mostly identical or fraternal?

A

1 in 90

30% identical, 70% fraternal

35
Q

Slightly more than half of all twins are (blank)

A

male

36
Q

What is the average birth weight for a singleton?

For a twin?

A

7lbs. 7oz

5lbs 5oz

37
Q

What is weird above twins hands?

A

35% left handed (double rate of general population)

38
Q

What ethnicity has the highest rates of twins?

A

A.A.> whites > orientals

39
Q

How does the placenta effect gas exchange?

A

maternal-> placenta: diffusion O2 from maternal circulation

placental -> fetus: direct delivery

40
Q

What does the placenta allow exchange for?

A

a.a, FFAs, vitamins, carbs

41
Q

How does the fetus get immunity?

A

through the placenta and passive diffusion of immunity from mom

42
Q

How does the placenta increase hormone production?

A

synctriotrophoblasts increase progesterone, estrogen, hCG, somatomammotropin (placental lactogens)