Placenta

Question 1

Human placenta is hemochorial, which means-

Answer 1

Maternal blood comes in direct contact with the chorion

Question 2

What is the fetal and maternal component of the placenta?

Answer 2

fetal- villous chorion

Maternal- decidua basalis

Question 3

The fetal surface of the placenta is characterized by

Answer 3

vascular chorionic plate covered by amnion; appears smooth and grayish

Question 4

The umbilical cord contains

Answer 4

2 umbilical arteries and 1 umbilical vein

Question 5

What are the umbilical arteries and vein surrounded by?

Answer 5

Wharton’s jelly (mucous connective tissue)

Question 6

Since umbilical vessels are longer than the cord, they twist around each other and bend forming

Answer 6

false knots

Question 7

What is the decidua

Answer 7

endometrium of the uterus in a pregnant woman

Question 8

What are the 3 regions of the decidua

Answer 8

Decidua basalis- part deep to the conceptus that forms the maternal part of placenta
Decidua capsularis- superficial part overlying conceptus
Decidua parietalis- all the reamining parts

Question 9

Maternal side of the placenta has 15-20 compartments called

Answer 9

cotyledons separated by placental septa

Question 10

Fetal component of the placenta is derived from the

Answer 10

trophoblast and extraembryonic mesoderm, forming the villous chorion

Question 11

What are the 3 stages of chorionic villi development

Answer 11

primary villi, secondary villi, and tertiary villi

Question 12

Cytotrophoblast cells penetrate through the synctiotrophoblast and reach the decade and form

Answer 12

the cytotrophoblast shell

Question 13

What does the cytotrophoblast shell do

Answer 13

firmly attaches chorion to the endometrium.

Question 14

What are villi that extend from the chorionic plate to the decidua basalis

Answer 14

Stem (anchoring) villi

Question 15

What branches from the sides of the stem villi and represent sites where nutrient and gas exchange will occur?

Answer 15

Terminal (free; branch) villi

Question 16

What is the placental membrane?

Answer 16

It separates the maternal blood from fetal blood

Question 17

By month 4, what are the 4 layers of the placental membrane

Answer 17

Synctiotrophoblast, cytotrophoblast, extraembryonic mesoderm, and fetal endothelium

Question 18

At the beginning of month 4, the cytotrophoblast degenerates leaving what 2 layers

Answer 18

Synctiotrophoblast and fetal endothelium

Question 19

In the 3rd trimester, what becomes very thin

Answer 19

syncytiotrophoblast

Question 20

What covers the surface of the chorion prior to week 8

Answer 20

Villi

Question 21

As pregnancy progresses, the villi proliferate to form the

Answer 21

chorionic frondosum (bushy chorion)

Question 22

Chorionic villi on the ab-embryonic pole degenerate and form __ by the end of month 3.

Answer 22

smooth chorionic laeve

Question 23

When can you conduct chorionic villus sampling

Answer 23

10-12 weeks

Question 24

What cells spread and form the lining of the amnion

Answer 24

epiblast cells

Question 25

The amnion encloses the entire embryo by

Answer 25

week 8

Question 26

The amnion becomes continuous with the skin at the attachment of the umbilical cord to the fetus to

Answer 26

cover the umbilical cord and placenta

Question 27

What are the functions of the amniotic fluid?

Answer 27

``` allows for fetal movements; Prevents adherence between amnion and embryo; shock absorber; barrier to infection; promotes lung development. ```

Question 28

What is the amniotic fluid volume at 10 weeks vs term

Answer 28

10 weeks- 30mL | 37 weeks- 1000 mL

Question 29

What is the "water-bag" that breaks prior to delivery of the baby?

Answer 29

amnio-chorionic membrane

Question 30

How is the amnio-chorionic cavity formed?

Answer 30

The amnion pushes against the chorion and the chorionic cavity is obliterated so the amnion lies against the chorionic laeve

Question 31

What is an amniocentesis

Answer 31

hollow needle is inserted through the mothers abdomen into the uterus and amniotic fluid is drawn for analysis

Question 32

What is amniotic band syndrome

Answer 32

There are tears in the amnion that may result in amniotic bands that encircle fetal limbs or digits resulting in deformations

Question 33

What is polyhydramnios and what is it correlated with

Answer 33

excess amniotic fluid; maternal diabetes and disorders of the central nervous system and GI tract that prevents fetus from swallowing.

Question 34

What is oligohydramnios and what is it linked to

Answer 34

too little amniotic fluid; may result from failure of the kidneys to form.

Question 35

What is oligohydramnios a risk factor of

Answer 35

lung hypoplasia (lung underdevelopment)

Question 36

What are the functions of the placenta?

Answer 36

``` Acts as an organ of exchange between maternal and fetal tissues; Produces hormones (progesterone, hCG, human placental lactogen=somatomammotropin) Serves as an immunological barrier ```

Question 37

What beneficial substances can cross the placenta?

Answer 37

``` Oxygen and CO2 glucose, amino acids, etc. Water, ions, etc. Urea, uric acid, bilirubin Maternal serum proteins unconjugated steroid hormones IgG, IgA ```

Question 38

What harmful substances can cross the placenta?

Answer 38

Viruses (rubella, CMV, herpes simplex type 2, measles, polio), toxoplasma gondii, and troponema pallidum (only bacteria that can cross). Category X drugs (absolute contraindication in pregnancy; thalidomide, coumadin, alcohol, etc.) Category D drugs (definite risk to fetus; tetracycline, valium, etc.) Carbon monoxide, mercury, lead, cocaine, heroin, rubella virus vaccine, anti Rh antibodies)

Question 39

What substances do not cross the placenta

Answer 39

Maternally derived cholesterol, triglycerides, phospholipids. Protein hormones- insulin IgD, IgE, IgM

Question 40

Umbilical arteries and veins carry what

Answer 40

arteries: deoxygenated blood toward placenta Vein: oxygenated blood toward fetus

Question 41

What is a newborns blood volume?

Answer 41

300 cc/mL

Question 42

The inner sac is the __ and outer sac is the __

Answer 42

amnion; chorion

Question 43

After 10 weeks amnion pushes out and

Answer 43

fuses with chorion

Question 44

What is delivery en caul?

Answer 44

sac is intact

Question 45

What are the metabolic functions of the placenta?

Answer 45

glycogen for fetus and cholesterol

Question 46

When is Rh disease a problem

Answer 46

Rh - mom and Rh + baby

Question 47

How to prevent Rh disease?

Answer 47

Give rhogam at 28 weeks, after baby is born if its Rh +, and after any bleeding in pregnancy

Question 48

Up to how many hours does rhogam work after bleeding?

Answer 48

72 hours

Question 49

What can cause postpartum hemorrhage?

Answer 49

leaving cotyledons behind after delivery

Question 50

What does marginal insertion (battledore) placenta cause

Answer 50

fetus may be small

Question 51

What occurs in membranous or velamentous insertion

Answer 51

cells can be kink, may result in non reassuring fetal heart tracing

Question 52

What is vasa previa

Answer 52

accessory placental lobe has vessels running across the internal opening of the cervix

Question 53

Why should you deliver vasa prevue babies early

Answer 53

If water breaks, vessels may rupture and baby can rapidly exsanguinate

Question 54

What is placenta previa?

Answer 54

Whole placenta is covering the opening of the cervix

Question 55

What is placenta accreta

Answer 55

placenta attaches too strongly to uterine muscle, or myometrium

Question 56

What is placenta increta

Answer 56

placenta invades into myometrium

Question 57

What is placenta percreta

Answer 57

placenta invades through myometrium to bowel, bladder

Question 58

What is abruption

Answer 58

Premature separation; babys oxygenation ceases and blood lost is fetal blood

Question 59

What causes abruption

Answer 59

cocaine, high BP, trauma

Question 60

Cleavage of morula in days 1-3 results in

Answer 60

dichorionic/diamniotic

Question 61

Cleavage of blastocyst in days 4-8

Answer 61

monochorionic/diamniotic

Question 62

Cleavage of implanted blastocyst in days 8-13

Answer 62

Monochorionic/monoamniotic

Question 63

Cleavage of formed embryonic disc in days 13-15

Answer 63

conjoined twins

Question 64

What is twin-twin transfusion syndrome?

Answer 64

if monochorionic, artery of one fetus can connect to vein of other, and blood from one baby flows to the other

Question 65

What happens to the fetuses in twin-twin transfusion

Answer 65

Donor: growth restricted, minimal fluid Recipient: fluid overload