OB Ch 55-57 Flashcards Preview

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Flashcards in OB Ch 55-57 Deck (74)
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1

What are the fetal membranes comprised off

-Chorion
-Amnion
-Allantos
-Yolk sac

2

Chorionic plate

The fetal surface of the placenta

3

Basal plate

The maternal surface of the placenta

4

Chorion frondosum

Forms the fetal part of the placenta and contains the villi

5

Chorion laeve

The nonvillious part of the chorion around the gestational sac

6

Decidua basalis

Decidua reaction that occurs between the blastocyst and the myometrium

7

Decidua capsularis

Decidua reaction that occurs over the blastocyst closest to the endometrial cavity

8

Decidua vera (parietalis)

Decidua reaction except for the areas beneath and above the implanted ovum

9

Functions of the placenta

-Respiration
-Nutrition
-Excretion
-Protection
-Storage
-Hormonal production

10

What is the major functioning unit of the placenta?

Chorionic villus

11

Velamentous placenta

Refers to the insertion of the umbilical cord that inserts on the membranes

12

Battledore placenta

Refers to the insertion of the umbilical cord at the margin of the placenta, within 10 mm of the edge

Labor may cause the cord to prolapse or be compressed during contractions

13

Weeks that the chorion and amnion fuse together

16th week

14

How big is the yolk sac

.8 mm

15

Function of hCG

-Causes the uterine endometrium to convert to decidua, a glycogen rich mucosa that nourishes the early pregnancy
-Keeps the corpus luteum functioning, so that the corpus luteum continues to produce estrogen and progesterone

16

Primary cause of placentomegaly

Maternal diabetes and Rh incompatibility

17

Common site of fibrin deposits

Appears as hypo echoic areas beneath the chorionic plate of the placenta

18

Complications of previa

-Preterm delivery
-Maternal hemorrhage
-Increased risk of placental invasion
-Increased risk of postpartum hemorrhage
-IUGR

19

Three placental invasions

-Percreta
-Increta
-Accreta

*Penetrates beyond the endometrial lining of the uterus

20

Placenta percreta

Penetration of the chorionic villi through(per-) the uterus

21

Placenta increta

Further extension of the chorionic villi into (in-) the myometrium

22

Placenta accreta

The chorionic villi attach to the myometrium without muscular invasion.
-Occurs in 1 to 2500 deliveries

23

Circumvallate

Attachment of the placenta membranes to the fetal surface of the placenta rather than to the underlying villous placental margin
-Occurs in 1-2% of pregnancies

24

Succenturiate

The presence of one or more accessory lobes connected to the body of the placenta-by-placenta vessels.
-Occurs in 3-6% of pregnancies
-Lobes develop infarcts and necrosis

25

Placental abruption

Refers to the separation of a normally implanted placenta prior to term delivery
-Occurs in 1 in 120 pregnancies
-Bleeding into the decidua basalis

26

Types of abruption

-Retroplacental abruption
-Marginal abruption

27

Retroplacental abruption

Results from the rupture of spiral arteries and is a "high pressure" bleed. Associated with hypertension and vascular disease.
-Hematoma is between the placenta and uterus

28

Marginal abruption

Most common type; also known as subchorionic bleeds.
Results from tears of the marginal veins and represents a "low pressure" bleed.
Hemorrhage arises from the edge of the placenta, dissects beneath the placental membranes
Associated with little placental detachment

29

Marginal previa

Does not cover the os, but its edge comes to the margin of the os

30

Complete previa

The cervical internal os is completely covered by placental tissue
-20% of patients