The Placenta

Question 1

Which part of the blastocyst develops into the placenta?

Answer 1

Trophoblast

Question 2

What is trophoblast?

Answer 2

Thin layer of cells that help a developing embryo attach to the wall of uterus, protect embryo and form part of placenta

Question 3

Trophoblast splits into 2 layers called

Answer 3

Syncytiotrophoblast (direct contact with maternal blood)

Cytotrophoblast (the inner layer)

Question 4

What layer of blastocyst is main layer for exchange of substances

Answer 4

Syncytiotrophoblast

Question 5

Uterus mainly supplied by which artery?

Answer 5

Uterine artery (branch of internal iliac artery)

Question 6

What is the blood supply to the placenta like?

Answer 6

Arcuate artery at myometrium
Spiral artery at endometrium
Blod flow to intervillous space

Question 7

Uterine contractions lead to an increase or decrease in fetal heart rate?

Answer 7

Decrease

Question 8

Umbilical contains how many arteries and veins

Answer 8

2 arteries (deoxygenated away from fetus)
1 vein (oxygenated to the fetus)

Question 9

What does human placental lactogen do?

Answer 9

Anti-insulin action makes more glucose available for fetus

Question 10

What does fetal haemogloin do to the bohr curve? which way does it shift?

Answer 10

Move to the left

Question 11

What is Rhesus Disease?

Answer 11

If mother rhesus-negative and baby rhesus- positive from father,
If mum exposed to positive rhesus antigen when exposed to fetus blood during delivery, mum produce rhesus D antibodies (IgG), which will affect future pregnancies
Antibody could attack red blood cells of fetus- haemolysis

Question 12

Which antibody can cross the placenta?

Answer 12

IgG and IgE

Question 13

Which antibody cannot cross placenta?

Answer 13

IgM

Question 14

What is given to mothers to prevent rhesus disease?

Answer 14

Anti-D immunoglobulin (Antibody) is given to Rh -ve mothers to prevent production of own antibodies

Question 15

Name the common placental abnormalities

Answer 15

Placenta praevia
Placental abruption
Prolapsed cord
Pre-eclampsia

Question 16

What is placenta praevia?

Symptoms?

Answer 16

When placenta lies close to/across the cervical os

Painless
Bleeding if rupture placenta

Question 17

What is placenta abruption?

Symptoms?

Answer 17

Bleeding in plane between placenta and uterus wall
Bleeding can be concealed or revealed
Can tamper how much fluid gets to baby, can be monitored
Complete separation=induce delivery- life threatening

Symptoms:
Painful due to stretching of membranes that have nociceptors
Can be bleeding shown

Question 18

What is a prolapsed cord?

Answer 18

an unborn baby’s umbilical cord slips through the cervix and into the vagina after a mother’s water breaks and before the baby descends into the birth canal

Membrane ruptures, umbilical cord goes down and bulges through cervix

Fetus head can discent and compress cord, cut off umbilical flow= fetal death

Caesarian section

Question 19

Pre-eclampsia symptoms

Answer 19

Maternal: high blood pressure, protein in urine, fluid retention, coagulopathy, renal damage, convulsions, liver damage

Question 20

What is an ‘En Caul’ birth?

Answer 20

Baby still in amniotic sac

Question 21

What is in the intervillous space?

Answer 21

Villi- large surface area for exchange