Module 9 : Normal Fetal Anatomy - Placenta and Cord Flashcards
(39 cards)
1
Q
at what week do we see two distinct components o the placenta
A
12 weeks
2
Q
two distinct components of the placenta
A
chorion frondosum
decidua basalis
3
Q
chorion frondosum
A
fetal portion
4
Q
decidua basalis
A
maternal portion
5
Q
how are the two layers held together
A
- anchoring or stem villi at the cytotrophoblastic shell
6
Q
intervilluous spaces
A
- syncytiotrophoblast cells create large spaces in the decidua basalis
7
Q
placental septa
A
- remaining projections of the decidua basalts
- septa divide the placenta into compartments
8
Q
cotyledon
A
- each compartment the septa divide into in the placenta
- consist of several stem villi
- about twenty in a placenta
9
Q
placenta membrane
A
- 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
Q
maternal circualtion
A
- spiral arterioles shoot blood around the chorionic villi
11
Q
fetal circulation
A
- from umbilical arteries to chorionic villi back to umbilical veins to baby
12
Q
functions of the placenta
A
- respiration (exchange oxygen)
- nutrition
- excretion (carbon dioxide)
- protection (toxic elements)
- storage
- hormonal production
13
Q
sonographic appearance
A
- 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
Q
grading of placenta
A
- grade 0 - 3
15
Q
grade 0 placenta
A
- homogenous
- chorionic plate is straight
16
Q
grade 1 placenta
A
- scattered echogenic areas
- subtle undulations
17
Q
grade 2 placenta
A
- indentations
- linear echogenic areas
18
Q
grade 3 placenta
A
- indentations to basal layer
- cystic areas
- shadowing calcifications
- after 36 weeks
19
Q
placenta shape
A
- flat and circular
20
Q
weight of placenta a
A
- 500-600 grams at term
21
Q
thickness of placenta
A
1.5-4 cm
22
Q
abnormal placenta thickness
A
> 4 cm
23
Q
growth of placenta per day
A
1mm
24
Q
measuring placenta
A
- 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
```
31
umbilical cord
- develops from connecting stock and yolk sac
- 2 arteries 1 vein
- vessels surrounded by whartons jelly
- covered with amnion
- 50-100 cm long
32
attachment of cord
- usually centre of placenta
- umbilical vein travels cephalic to portal sinus
- umbilical arteries travel caudal around fetal bladder to hypogastric arteries in fetus
33
single umbilical artery
- associated with cardiac and renal anomalies
- associated with chromosomal abnormalities
- often isolated finding and very common
34
other cord anomalies
- hematoma
- cord cyst
- umbilical vein thrombosis
- omphalocele
- cord prolapse
35
hematoma
- from trauma of wall weakness
| - results in perinatal death
36
cord cyst
- allantoid remnant
| - insignificant
37
umbilical vein thrombus
- umbilical vein varix (dilation) or blockage
| - results in perinatal death
38
omphalocele
- liver outside of abdomen
39
cord prolapse
- cord slips into cervix and vagina
| - NOT GOOD
