Placental Morphogenesis and Function

Question 1

angioblasts

• differentiate into?
• derived from?

Answer 1

Angioblasts are derived from the mesenchymal cells of the embryonic and extraembryonic mesoderm. They differentiate into primitive red blood cells, or transform into endothelial cells to produce capillaries

Question 2

Chorionic Villi

• begin as? (what type of cell)
• Primary Villi
• Secondary Villi
• Tertiary villi

Answer 2

Chorionic Villi

• begin as cytotrophoblast cells that organize into columns that extend through the syncytiotrophoblast
• Primary Villi-cytotrophoblast cells surrounded by syncytiotrophoblast
• Secondary Villi- when the extraembryonic mesoderm penetrates the cytotrophoblast creating mesodermal cores
• Tertiary villi- embryonic blood vessels develop in the cores of the secondary villi

Question 3

Stem Villi

Answer 3

Stem Villi are the villi that extend completely through the syncytiotrophoblast

Question 4

Terminal Villi

Answer 4

Terminal Villi branch off of the stem villi and serve in nutrient exchange in the placenta

Question 5

Hemolytic Anemia of the fetus or newborn

Answer 5

Hemolytic anemia of the fetus or newborn is any anemia of pregnancy resulting from excessive destruction of fetal RBCs.

Question 6

Erythroblastosis fetalis

Answer 6

Erythroblastosis fetalis is any hemolytic anemia of pregnancy resulting from isoimmunization, such as Rh incompatibility

Question 7

Hydrops Fetalis

• how do you diagnose it?
• how can you treat it?

Answer 7

Hydrops Fetalis is an extreme case of erythroblastosis fetalis characterized by edema, elevated bilirubin, brain damage, and neonatal demise

• you can diagnose the severity of the syndrome by spectrophotoetric analysis of amniotic fluid
• treatment is with intrauterine transfusion of RBC packed blood

Question 8

Treatment for Rh incompatibility

• goal for treatment
• most common allele of Rh antigen?

Answer 8

Treatment for Rh incompatibility is to treat the mother with RhoGam (anti-RhoD antibodies) just after any mixing of fetal (Rh +) blood and maternal blood (Rh -) might have occurred. The mixing of blood most often occurs when the placenta releases from the uterine wall during birth which causes some bleeding. another route is placenta abruptio- when the placenta ruptures or separates from the uterine wall resulting in uterine bleeding
the goal for treatment with RhoGam is to use injected antibodies to clear any fetal Rh+ blood from the maternal system before they can illicit an immune response from the mother. It is usually administered at 28 weeks of gestation and after delivery, but can be given any time there is a suspicion of placental bleeding (miscarriage, vaginal bleeding, or abdominal trauma)

Question 9

what is the origin of the maternal side of the placenta?

Answer 9

the maternal side of the placenta is derived from the trophoblastic lacunae that form in the syncytiotrophoblast. They expand and coalesce with glands and capillaries in the endometrium to form maternal sinusoids (they are filled with maternal blood)

Question 10

What maternal organ destroys fetal Rh+ cells

Answer 10

The spleen of an Rh- mother will destroy any Rh+ RBC of the fetus. This is what illicits the immune response and formation of Rh antibodies