Placental Physiology Flashcards
Name the 3 vessels within the umbilical cord.
What type of blood are they carrying where?
- 2 umbilical arteries
- Carry deoxygenated blood from fetal internal iliac to placenta
- 1 umbilical vein
- Carries oxygenated blood from placenta to fetal IVC
Compare the location and function of syncytiotrophoblast v cytotrophoblast
-
Syncytiotrophoblast
- __Outler layer of chorionic villi
- Invades into uterine wall and synthesizes hormones
-
Cytotrophoblast
- __Inner layer of chorionic villi (closer to fetus)
- Makes cells
What are the two types of chorionic villi and what are their functions?
Floating vili - site of nutrient/waste exchange
Anchoring vili- attach to uterus
How deep do syncytiotrophoblasts invade? (2)
Through endometrium into myometrium
Also invade uterine artery walls to replace the myocytes
How does the syncytiotrophoblast avoid being attacked by mom’s immune system?
Lacks expression of MHC-I
Compare the oxygen affinity of HbF and HbA
Why does this occur?
Fetal Hb has a higher O2 affinity than HbA (left shift)
Due to decreased affinity for 2,3 BPG
When does the placenta take over production of steroid hormones?
Week 8
(corpus luteum producing hormones under influence of hCG until then)
Compare the levels of hCG, AFP, and inhibin in
Trisomy 21, 18, 13
- Trisomy 21
- low AFP
- high hCG
- high inhibin
- Trisomy 18
- All low (inhibin may be normal)
- Trisomy 13
- All normal (hCG may be low)
What is the main function of human placental lactogen?
Where is it made?
Causes mom to be insulin resistant so that she shifts to fatty acid metabolism and glucose can go to fetus
Synthesized by syncytiotrophoblast
How does progesterone affect….
- Endometrium (2)
- Myometrium
- Cervical mucus
- Body temperature
- LH/FSH
- Prevents endometrial hyperplasia & stimulates endometrial secretions
- Causes relaxation of myometrium
- Creates thick cervical mucous
- Causes increased body temperature
- Suppresses LH/FSH
Are steroid hormones produced in the maternal, fetus, or placenta?
Steroid hormones can only be produced when all of these parts are working together!
(each part has specific enzyme deficiencies)
What immunoglobulins are present in the fetus?
Where did they come from?
- Fetus receives IgG from mom
- Fetus makes own IgM
Amniotic fluid is needed for development of what two fetal structures?
Lungs
Limbs
What are the components of amniotic fluid? (2)
maternal plasma filtrate and fetal urine
Cause of oligohydramnios (1)
Causes of polyhydramnios (2)
Oligohydramnios = kidney problem
Polyhydramnios = swallowing problem or diabetes
