Module 9 : Normal Fetal Anatomy - Placenta and Cord Flashcards Preview

Ob/Gyne > Module 9 : Normal Fetal Anatomy - Placenta and Cord > Flashcards

Flashcards in Module 9 : Normal Fetal Anatomy - Placenta and Cord Deck (39)
Loading flashcards...
1

at what week do we see two distinct components o the placenta

12 weeks

2

two distinct components of the placenta

chorion frondosum
decidua basalis

3

chorion frondosum

fetal portion

4

decidua basalis

maternal portion

5

how are the two layers held together

- anchoring or stem villi at the cytotrophoblastic shell

6

intervilluous spaces

- syncytiotrophoblast cells create large spaces in the decidua basalis

7

placental septa

- remaining projections of the decidua basalts
- septa divide the placenta into compartments

8

cotyledon

- each compartment the septa divide into in the placenta
- consist of several stem villi
- about twenty in a placenta

9

placenta membrane

- separates the fetal blood in the capillaries of the CHORIONIC VILLI from the maternal blood in the INTERVILLOUS SPACES
- maternal blood enters the intervillous spaces via the spiral arterioles

10

maternal circualtion

- spiral arterioles shoot blood around the chorionic villi

11

fetal circulation

- from umbilical arteries to chorionic villi back to umbilical veins to baby

12

functions of the placenta

- respiration (exchange oxygen)
- nutrition
- excretion (carbon dioxide)
- protection (toxic elements)
- storage
- hormonal production

13

sonographic appearance

- early = homogenous
- venous lakes along the basal plate and in the septa
- may see calcifications later in pregnancy due to maternal serum calcium levels

14

grading of placenta

- grade 0 - 3

15

grade 0 placenta

- homogenous
- chorionic plate is straight

16

grade 1 placenta

- scattered echogenic areas
- subtle undulations

17

grade 2 placenta

- indentations
- linear echogenic areas

18

grade 3 placenta

- indentations to basal layer
- cystic areas
- shadowing calcifications
- after 36 weeks

19

placenta shape

- flat and circular

20

weight of placenta a

- 500-600 grams at term

21

thickness of placenta

1.5-4 cm

22

abnormal placenta thickness

> 4 cm

23

growth of placenta per day

1mm

24

measuring placenta

- do not include retroplacenta complex (basal layer)

25

placentamegaly

> 4cm thick

26

causes of placentamegaly

- maternal diabetes
- maternal anemia
- hydrops
- placenta hemorrhage
- intrauterine infection
- partial mole
- chromosomal abnormalities

27

complete molar pregnancy

- triploidy 69 chromosomes
- uterus full of placenta
- no embryo
- if not removed can lead to chorionic carcinoma

28

thin placenta

- placenta insufficiency
- may cause IUGR
- < 1.5 cm

29

causes of thin placenta

- vascular deficiencies or infarction
- pre eclampsia = a toxaemia of late pregnancy (hypertension, protein urie, edema)

30

contraction vs fibroid

- fibroid
+ muscular tumor benign
+ lasts long time
- contraction
+ Braxton hicks
+ will go away after time