The Placenta Flashcards
Which part of the blastocyst develops into the placenta?
Trophoblast
What is trophoblast?
Thin layer of cells that help a developing embryo attach to the wall of uterus, protect embryo and form part of placenta
Trophoblast splits into 2 layers called
Syncytiotrophoblast (direct contact with maternal blood)
Cytotrophoblast (the inner layer)
What layer of blastocyst is main layer for exchange of substances
Syncytiotrophoblast
Uterus mainly supplied by which artery?
Uterine artery (branch of internal iliac artery)
What is the blood supply to the placenta like?
Arcuate artery at myometrium
Spiral artery at endometrium
Blod flow to intervillous space
Uterine contractions lead to an increase or decrease in fetal heart rate?
Decrease
Umbilical contains how many arteries and veins
2 arteries (deoxygenated away from fetus) 1 vein (oxygenated to the fetus)
What does human placental lactogen do?
Anti-insulin action makes more glucose available for fetus
What does fetal haemogloin do to the bohr curve? which way does it shift?
Move to the left
What is Rhesus Disease?
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
Which antibody can cross the placenta?
IgG and IgE
Which antibody cannot cross placenta?
IgM
What is given to mothers to prevent rhesus disease?
Anti-D immunoglobulin (Antibody) is given to Rh -ve mothers to prevent production of own antibodies
Name the common placental abnormalities
Placenta praevia
Placental abruption
Prolapsed cord
Pre-eclampsia
What is placenta praevia?
Symptoms?
When placenta lies close to/across the cervical os
Painless
Bleeding if rupture placenta
What is placenta abruption?
Symptoms?
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
What is a prolapsed cord?
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
Pre-eclampsia symptoms
Maternal: high blood pressure, protein in urine, fluid retention, coagulopathy, renal damage, convulsions, liver damage
What is an ‘En Caul’ birth?
Baby still in amniotic sac
What is in the intervillous space?
Villi- large surface area for exchange
