1d.Twinning - placenta - ubilical cord Flashcards Preview

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Flashcards in 1d.Twinning - placenta - ubilical cord Deck (26):
1

Dizygotic twins are ____ (dichorionic/monochorionic) and ____ (diamniotic/monoamniotic).

Dichorionic; diamniotic

2

How many chorion(s) and amniotic sac(s) should be present in a patient pregnant with conjoined twins?

One chorion and one amniotic sac

3

A patient has dizygotic twins. How many egg(s) and sperm(s) do dizygotic twins arise from?

Two eggs, separately fertilized by two sperm

4

A patient has monozygotic twins. How many egg(s) and sperm(s) do monozygotic twins arise from?

One egg and one sperm; monozygotic twins arise from splitting of the fertilized egg into two zygotes in early pregnancy

5

A morula is cleaved just before becoming a blastocyst. What type of twin pregnancy would result?

Monozygotic monochorionic diamniotic twins

6

A patient has monozygotic dichorionic diamniotic twins. Between what two stages of the zygote did cleavage occur?

Between two-cell stage and morula stage

7

A blastocyst is cleaved just before forming the embryonic disc. What type of twin pregnancy would result?

Monozygotic monochorionic monoamniotic twins

8

A patient gives birth to monozygotic monochorionic monoamniotic conjoined twins. Where in the growth process did cleavage occur?

Cleavage occurred after the embryonic disc was formed

9

Which layer of the chorionic villi secretes human chorionic gonadotropin?

Outer layer (the syncytiotrophoblast)

10

Is the decidua basalis (see image) derived from the maternal or fetal component of the placenta?

Maternal endometrium, with maternal blood in lacunae

11

What stimulates the corpus luteum to secrete progesterone during the first trimester of pregnancy?

Human chorionic gonadotropin, which is structurally similar to luteinizing hormone (LH)

12

What is the primary site of nutrient and gas exchange between the mother and fetus?

The placenta

13

Which layer of the chorionic villi is mitotically active?

Inner layer (the Cytotrophoblast), which makes cells

14

Tests on syncytiotrophoblastic tissue show low MHC-I expression. If white blood cells are introduced, do they show an increase in activity?

Unlikely (the lack of MHC-I expression in the syncytiotrophoblast means that a decreased chance of attack by maternal immune system)

15

Do the umbilical arteries carry oxygenated or deoxygenated blood?

Deoxygenated blood

16

The umbilical arteries shunt blood to the placenta out of which arteries in the fetus?

The fetal internal iliac arteries

17

Does the umbilical vein carry oxygenated or deoxygenated blood?

Oxygenated blood

18

You just delivered a baby. Why should you take a good look at the cord and document the number of umbilical arteries?

A single umbilical artery is associated with congenital and chromosomal anomalies

19

From which fetal structure are the umbilical arteries and veins derived?

The allantois

20

The umbilical vein drains into the IVC via which structure(s)?

Liver or ductus venosus

21

Normally, how many umbilical artery(ies) and vein(s) are present?

Two umbilical arteries and one umbilical vein

22

The image shows cross section of a structure that allows transfer of oxygenated/deoxygenated blood between mother and fetus. Name it.

Umbilical cord

23

A newborn's umbilical cord shows an anomaly that makes you feel worried (shown in image). What is the anomaly?

A single umbilical artery (two-vessel cord), which is associated with congenital and chromosomal anomalies

24

What structure connects the fetal bladder with the yolk sac and removes nitrogenous waste from the fetal bladder?

The urachus (formed from allantois in the third week)

25

Which two structures are connected by the vitelline duct?

The vitelline duct (omphalomesenteric duct) connects the yolk sac to the midgut lumen

26

In what week of gestation does the vitelline duct obliterate?

In the seventh week