Placenta, Amniotic Fluid and Umbillical Cord

Question 1

What is the placenta?

Answer 1

A temporary organ that forms when the chorion does. It develops villi to exchange oxygen and transfers substances between mother and fetus.

Question 2

When does the placenta form?

Answer 2

When the trophoblast forms the chorion.

Question 3

What is the embryonic portion of the placenta?

Answer 3

chorion frondosum

Question 4

What is the maternal portion of the placenta?

Answer 4

decidua basalis

Question 5

What is the decidua?

Answer 5

The endometrial lining of the uterine cavity.

Question 6

What is the decidua basalis?

Answer 6

portion of the endometrium undelrying the implantation site.

Question 7

What does the decidua capsularis cover?

Answer 7

the portion overlying the embryo; it separates it from the uterine cavity.

Question 8

What is the decidua parietalis?

Answer 8

The remainder of the endometrium.

Question 9

Where do villi develop on the fetal part of the placenta, and what do they do?

Answer 9

chorion fondosum; they allow for the exchange between maternal and fetal systems. Capillaries also form in this area.

Question 10

What are the components of the exchange system?

Answer 10

amnion, chrionic plate, umbillical cord and basal plate.

Question 11

Where do primary chorionic villi protrude from?

Answer 11

from the cytotrophoblast (they are segments of it) to the synciotrophoblast.

Question 12

What do chorionic villi do?

Answer 12

give oxygen and nutrients from maternal blood to the fetus via diffusion; also diffuse from blood through the walls to the maternal blood.

Question 13

What do tertiary chorionic villi contain?

Answer 13

embryonic blood vessesls; they connect with vessels in the chorion and connecting stalk to eventually (3rd week) circulate blood.

Question 14

Fetal hemoglobin has a higher affinity for what?

Answer 14

Oxygen; is due to the short barrier that they must cross.

Question 15

what is the placental membrane?

Answer 15

A membrane that allows substances to flow from the placenta into embryonic tissue. Oxygen, co2, glucose, fatty acids and vitamins are beneficial.

Question 16

What are some dangerous things that cross the barrier?

Answer 16

Isotretinoin (acne medication), thalidomide, alcohol, illegal drugs, some viruses (e.g. herpes).

Question 17

What is the Rh factor?

Answer 17

an antigen in blood cells. If the mother is Rh negative and the fetus is Rh positive, the mother will produce antibodies that could be harmful in a second pregnancy.

Question 18

What are symptoms of Rh factor?

Answer 18

Swelling, collection of fluid in the tissues, jaundice, anemia.

Question 19

How is Rh factor treated?

Answer 19

RhoGAM

Question 20

What is the cotyledon

Answer 20

It contains large vessels that feeds into smaller placental vesicles. It ia section there are 20 - 25) of the decidius basalis. They contain chorionic villi and receive blood from chorionic vessels.

Question 21

What is the purpose of chrionic villus sampling?

Answer 21

To test for genetic disorders from 10 - 20 weeks.

Question 22

What is Wharton’s Jelly?

Answer 22

Connective tissue in the umbillical cord. IT increases in volume to allow closure of blood vessels.

Question 23

Which umbilical vein regresses?

Answer 23

The right.

Question 24

What does the left umbilical vein do?

Answer 24

delivers blood from the placentra to the fetus.

Question 25

Why can a velamentous cord be dangerous?

Answer 25

more vessels are exposed to trauma during childbirth.

Question 26

Where are normal placental implantation sites?

Answer 26

anterior, posterior and fundal (cranial position in uterus)

Question 27

placenta previa

Answer 27

implantation of the placenta over the cervical os (opening).

Question 28

placentra accreta

Answer 28

abnormal trophoblastic invasion into the muscular layer (increta) or the surrounding tissues (percerta).

Question 29

What can the placenta synthesize

Answer 29

glycogen, cholesterol, fatty acids, nutrients and some globulin.

Question 30

Where are most hormones syntheisized?

Answer 30

synciotrophoblast.

Question 31

What hormone in the placenta induces lipolysis?

Answer 31

human placental lactogen/chorionic somatommammotropin; also known as the "growth hormone" of the fetus.

Question 32

What does progesterone do?

Answer 32

maintains the endometrial lining during pregnancy and suppressed contractility in the uterine smooth muscle.

Question 33

What is calcification?

Answer 33

A sign of placental aging; can affect the blood supply to the fetus. It is why pregnancies should not go too long past the due date.

Question 34

What is the amniotic fluid?

Answer 34

Fluid surrounding the embryyo. It allows for symmetrial growth and movement (especially of lungs); it prevents infection, maintains homeostasis, and prevents sticking of the embryo to the amnion.

Question 35

What is oligohydramnios?

Answer 35

A low volume of amniotic fluid associated with failure of kidneys and lungs to develop (potter syndrome).

Question 36

What is polyhydramnios?

Answer 36

A high volume of amniotic fluid associated with CNS aomalies and closure of the esophagus or intestines.

Question 37

What is amniotic band syndrome?

Answer 37

Tears in the amnion that detach and surround the fetus.

Question 38

How are vessels formed?

Answer 38

Vasculogenesis or angiogenesis. (around the yolk sac and chorion)

Question 39

What are blood islands?

Answer 39

Regions of the connecting stalk that eventually form vessels.

Question 40

What is angiogenesis?

Answer 40

formation of vessels from existing vessels.

Question 41

What organ of the fetus creates red and white blood cells?

Answer 41

the liver.

Question 42

What cells that create RBC/WBC eventually become the liver?

Answer 42

aorta-gonad-mesonephros region (AGM) cells.

Question 43

What do the umbilical veins and arteries do?

Answer 43

The umbilical vein carries oxygenated, nutrient-rich blood from the placenta to the fetus, and the umbilical arteries carry deoxygenated, nutrient-depleted blood from the fetus to the placenta