Placenta Yan

Question 1

What makes up a blastocyste?

Answer 1

an inner cell mass and outter cell mass (trophoblast)

Question 2

What happens on day 6 of fertilization?

Answer 2

trophoblast cells of blastocyst invades uterine epithelium

Question 3

What happens on day 8 of fertilization?

Answer 3

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

Question 4

What happens on day 9 of fertilization?

Answer 4

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

Question 5

What is the closure of the penetration defect called?

Answer 5

the fibrin coagulum

Question 6

How do we get to the lacunar stage?

Answer 6

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

Question 7

What happens on Day 11 and 12 of fertilization?

Answer 7

establishment of uteroplacental circulation

maternal blood enters

Question 8

How do we get uteroplacental circulation?

Answer 8

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

Question 9

What happens on day 13 of fertilization?

Answer 9

Primary villi fomration

Question 10

How do we get primary villi formation?

Answer 10

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

Question 11

How do we get secondary villus formation?

Answer 11

mesodermal cells penetrate the core of 1st villi

Question 12

How do we get a tertiary villus formation?

Answer 12

mesoderm cells become blood cells and blood vessels

Question 13

At the end of the third week, what happens?

Answer 13

maternal vessels penetrate cytotrophoblastic shell and enter intervillous space

Question 14

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

Answer 14

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

Question 15

At the end of the 3rd week what happens?

Answer 15

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

Question 16

What are the intervillous spaces lined with?

Answer 16

synctium

Question 17

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

Answer 17

cytotrophoblastic cells

Question 18

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

Answer 18

connecting stalk

Question 19

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

Answer 19

synctium
cytotrophoblast
CT
endothelium

Question 20

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

Answer 20

synctium

endothelium

Question 21

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

Answer 21

villi at the abembryonic pole forming chorion laeve

Question 22

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

Answer 22

amnion and chorion fuse

uterine cavity is obliterated

Question 23

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

Answer 23

by the fusion of chorion laeve and deciuda parietalis

Question 24

How big is a full-term placenta?

Answer 24

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

Question 25

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

Answer 25

30 minutes

Question 26

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

Answer 26

amnion, umbilical cord, chorionic plate, chorion vessels

Question 27

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

Answer 27

cotyldon and decidua basalis

Question 28

How do you get dizygotic twins?

Answer 28

you ovulate 2 eggs at the same time

Question 29

How do you get monozygotic twins?

Answer 29

one egg splits into 2

Question 30

What are the 2 kinds of possible dizygotic twin?

Answer 30

separate placenta and chorion | fusion of placenta and chorion

Question 31

What are the 3 kinds of possible monozygotic twins?

Answer 31

separate placenta and chorion common placenta common amniotic cavity

Question 32

How do you get monozygotic twins with a common placenta?

Answer 32

you get dont get separate chorions

Question 33

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

Answer 33

the amniotic cavities are fused and do not separate

Question 34

How often do you get twin conceptions? | Mostly identical or fraternal?

Answer 34

1 in 90 | 30% identical, 70% fraternal

Question 35

Slightly more than half of all twins are (blank)

Answer 35

male

Question 36

What is the average birth weight for a singleton? | For a twin?

Answer 36

7lbs. 7oz | 5lbs 5oz

Question 37

What is weird above twins hands?

Answer 37

35% left handed (double rate of general population)

Question 38

What ethnicity has the highest rates of twins?

Answer 38

A.A.> whites > orientals

Question 39

How does the placenta effect gas exchange?

Answer 39

maternal-> placenta: diffusion O2 from maternal circulation | placental -> fetus: direct delivery

Question 40

What does the placenta allow exchange for?

Answer 40

a.a, FFAs, vitamins, carbs

Question 41

How does the fetus get immunity?

Answer 41

through the placenta and passive diffusion of immunity from mom

Question 42

How does the placenta increase hormone production?

Answer 42

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