3: Placenta And Fetal Membranes

Question 1

Two components of the placenta

Answer 1

Fetal part: chorion

Maternal part: derived from endometrium

Question 2

Formation of lacunar networks during implantation

Answer 2

1. Lacunae appear in syncytiotrophoblast layer -> fill with blood and uterine secretions
2. Adjacent lacuae fuse -> intervillous space

Question 3

Extraembryonic coelom

Answer 3

Fluid-filled cavity around amnion and umbilical vesicle

Question 4

What does the amnion become once it obliterates?

Answer 4

Epithelial covering of the umbilical cord

Question 5

Polyhydramnios

Answer 5

Excess amniotic fluid due to genetic/CNS/or GI abnormalities

Question 6

Clinical signs of polyhydramnios

Answer 6

Abdominal pain, significant swelling, SOA

Question 7

Polyhydramnios increases risk for what?

Answer 7

PROM (premature rupture)

Question 8

Oligohydramnios definition

Answer 8

Insufficient amniotic fluid, less than 400 mL

Question 9

What can oligohydramnios cause?

Answer 9

Anomalies in development (renal agenesis, pulmonary hypoplasia), placental abnormalities, maternal hypertension

Question 10

Three things that do not cross placenta

Answer 10

1. Protein hormones
2. Bacteria
3. Drugs with AA structure

Question 11

Things that can cross placenta

Answer 11

Nutrients, IgG, insulin, T3/T4, cholesterol hormones, waste products, drugs, infectious agents

Question 12

Name some drugs that do cross placenta

Answer 12

Alcohol, cocaine, heroine, labor management drugs

Question 13

Name some infectious agents that can cross placenta

Answer 13

cytomegalovirus, rubella, varicella, measles, herpes, toxoplasma Gondii, etc

Question 14

Histo of umbilical cord

Answer 14

Wharton’s jelly

Question 15

Formation of the umbilical cord

Answer 15

Connecting stalk enveloped by amnion

Question 16

Umbilical arteries and veins

Answer 16

2 arteries: deox fetal blood

1 vein: 80% oxygenated fetal blood

Question 17

What can absence of 1+ umbilical artery cause?

Answer 17

Can impact third trimester outcomes

Question 18

Most common type of abnormal placentation

Answer 18

Placenta previa

Question 19

Two predisposing factors for placenta previa

Answer 19

Prior placenta previa (60%), Hx previous Caesarian

Question 20

Hydatidiform mole

Answer 20

Replacement of normal villi by dilated/hydropic translucent vesicles

Question 21

Dx of invasive mole vs gestational choriocarcinoma

Answer 21

Invasive mole: persistent high blood hCH

Gestational choriocarcinoma: increasing hCG titer with no uterine elargement

Question 22

Dizygotic twins anmions and chorions

Answer 22

Each have thier own

Question 23

Three stages of monozygotic twin membrane division

Answer 23

2-8 cell stage -> diamniotic + dichorionic
Blastocyst (4-8 cells) -> diamniotic + monochorionic
Implanted (9-12 days) -> monoamniotic + monochorionic