Hy Embryology 05

Front 1

When is the placenta formed?

Back 1

When the embryo invades the endometrium of the uterus and when the trophoblast forms the villous chorion

Front 2

Describe the stages of villous chorion formation

Back 2

1. Primary chorionic villi
2. Secondary chorionic villi
3. Tertiary chorionic villi

Front 3

Describe the decidua basalis

Back 3

1. The maternal component of the placenta
2. Derived from the endometrium of the uterus located between the blastocyst and the myometrium

Front 4

What is the maternal component of the placenta?

Back 4

Decidua basalis

Front 5

Describe the origin of the decidua basalis

Back 5

Derived from the endometrium of the uterus located between the blastocyst and the myometrium

Front 6

Describe the decidua parietalis

Back 6

All portions of the endometrium other than the site of implantation

Front 7

What components of the placenta are shed as part of the after birth

Back 7

Decidua basalis and the decidua parietalis

Front 8

Describe the decidua capsularis

Back 8

The portion of the blastocyst that separates it from the uterine cavity, becomes attenuated and degenerates at week 22 of development because of a reduced blood supply

Front 9

What is the portion of the endometrium that covers the blastocyst?

Back 9

Decidua capsularis

Front 10

When and why does the decidua capsularis degenerate?

Back 10

At week 22 of development due to reduced blood supply

Front 11

Describe the maternal surface of the placenta

Back 11

1. Characterized by 8-10 compartments called cotyledons (imparting a cobblestone appearance), which are seperated by decidual (placental) septa
2. Dark red in color and oozes blood due to torn maternal blood vessels

Front 12

What are cotyledons?

Back 12

The compartments that characterized the maternal surface of the placenta

Front 13

Describe the fetal component of the placenta

Back 13

Consists of tertiary chorionic villi derived from both the ptrophoclast and extraembryonic mesoderm, which collectively become known as the villous chorion

Front 14

What is the villous chorion?

Back 14

The part of the chorion where the villi persist and form the fetal part of the placenta.

Front 15

Where does the villous chorion develop most prolifically?

Back 15

At the site of the decidua basalis

Front 16

What is the smooth chorion?

Back 16

1. An area of no villus development
2. Related to the decidua capsularis

Front 17

Describe the fetal surface of the placenta

Back 17

1. Characterized by well-vascularized chorionic plate containing the chorionic (fetal) blood vessels
2. Smooth, shiny, light-blue or blue-pink appearance (because the amnion covers the fetal surface)
3. 5-8 large chorionic (fetal) blood vessels should be apparent

Front 18

Describe Velamentous placenta

Back 18

1. Occurs when the umbilical (fetal) blood vessels abnormally travel through the amniochorionic membrane before reaching the placenta proper
2. If the umbilical (fetal) blood vessels cross the internal os, a serious condition called vasa previa exists
3. In vasa previa, if one of the umbilical (fetal) blood vessels ruptures during pregnancy, labor, or delivery the fetus will bleed to death

Front 19

Describe placenta previa

Back 19

1. Occurs when the placenta attaches in the lower part of the uterum, coverting the internal os
2. The placenta normally implants in the posterior superior wall of the uterus
3. Uterine (maternal) blood vessels rupture during the later part of pregnancy as the uterus begins to gradually dilate
4. The mother may bleed to death and the fetus will also be placed in jeopardy becasuse of the compromised blood supply
5. Because the placenta blocks the cervical opening, delivery is usually accomplished by C-section
6. This condition is clinically associated with repeated episodes of bright-red vaginal bleeding
7. Placenta previa is the classic cause of third trimester bleeding, whereas, an ectopic pregnancy is the classic cause of first-trimester bleeding

Front 20

Where does the placenta normally implant?

Back 20

Posterior superior wall of the uterus

Front 21

Describe delivery with placenta previa

Back 21

Because the placenta blocks the cervical opening, delivery is usually accomplished by C-section

Front 22

Describe placenta previa clinically

Back 22

This condition is clinically associated with repeated episodes of bright-red vaginal bleeding

Front 23

What is the classic cause of third trimester bleeding?

Back 23

Placenta previa

Front 24

What is the classic cause of first trimester bleeding?

Back 24

Ectopic pregnancy

Front 25

What are the risk factors for placenta accreta/increta/percreta?

Back 25

Risk factors include multiple curettages, previous C-sections, severe endometritis, or closely spaced pregnancies

Front 26

Describe placenta accreta

Back 26

1. Occurs when a placenta implants on the myometrium
2. This results in retained placenta and hemorrhage nad may lead to uterine rupture (placenta percreta)
3. Risk factors include multiple curettages, previous C-sections, severe endometritis, or closely spaced pregnancies

Front 27

Describe placenta increta

Back 27

1. Occurs when a placenta implants deep into the myometrium
2. This resutls in retained placenta and hemorrhage nad may lead to uterine rupture (placenta percreta)
3. Risk factors include multiple curettages, previous C-sections, severe endometritis, or closely spaced pregnancies

Front 28

Describe placenta percreta

Back 28

1. Occurs when a placenta implants through the wall of the uterus
2. This resutls in retained placenta and hemorrhage nad may lead to uterine rupture (placenta percreta)
3. Risk facotrs include multiple curettages, previous C-sections, severe endometritis, or closely spaced pregnancies

Front 29

What is severe preeclampsia?

Back 29

Severe preeclampsia refers to the sudden development of maternal hypertension (>160/110 mmHg), edema (hands and/or face), and proteinuria (>5g/24hr) usually after week 32 of gestation (third trimester)

Front 30

What is severe eclapsia?

Back 30

Severe preeclampsia refers to the sudden development of maternal hypertension (>160/110 mmHg), edema (hands and/or face), proteinuria (>5g/24hr), and convulsions usually after week 32 of gestation (third trimester)

Front 31

Describe the pathophysiology of preeclampsia

Back 31

Involves a generalized arteriolar constriction that impacts the brain (seizures and stroke), kidneys (oliguria and renal failure), liver (edema), and small blood vessels (thrombocytopenia and DIC).

Front 32

Describe treatment of preeclampsia

Back 32

Treatment of severe preeclampsia involves magnesium sulfate (for seizure prophylaxis) and hydralazine (BP control).

Front 33

Describe the risk factors for preeclampsia/eclampsia

Back 33

-Nulliparity
-Diabetes
-Hypertension
-Renal disease
-Twin gestation
-Hydatidiform mole (produces first-trimester preeclampsia)

Front 34

What can produce first-trimester preeclampsia?

Back 34

Hydatidiform mole

Front 35

Describe Preeclamsia and eclampsia

Back 35

1. Severe preeclampsia refers to the sudden development of maternal hypertension (>160/110 mmHg), edema (hands and/or face), and proteinuria (>5g/24hr) usually after week 32 of gestation (third trimester)
2. Eclampsia includes the additional symptom of convulsions
3. The pathophysiology of preeclampsia involves a generalized arteriolar constriction that impacts the brain (seizures and stroke), kidneys (oliguria and renal failure), liver (edema), and small blood vessels (thrombocytopenia and DIC).
4. Treatment of severe preeclampsia involves magnesium sulfate (for seizure prophylaxis) and hydralazine (BP control).
5. Once the patient is stabilized, delivery of fetus should ensue immediately.
6. Risk factors include nulliparity, diabetes, hypertension, renal disease, twin gestation, or hydatidiform mole (produces first-trimester preeclampsia)