When does the embryo invade the endometrium? Day 7 What does
hCG stand for? Human chorionic gonadotropin Where is is secreted
from? Trophectoderm When is hCG first detectable? Day 8
Slide 3
What are the THREE aims of the implantation? (in terms of
placenta..) 1.Anchor the placenta 2.Establishment of basic unit of
exchange between fetus and mother 3.Establishment of blood flow
within the placenta
Slide 4
What is the function of hCG? Maintains the corpus lutem Why is
this required? Corpus luteum produced progesterone. Progesterone
maintains the endometrium until the placenta can take over. What
are the three stages/classifications of the villus? Primary
syncytio trophoblast penetrated by cords of cytotrophoblast
Secondary penetrated by mesenchymal cells Tertiary penetrated by
fetal vessels
Slide 5
How does the villus further develop to adapt to the increasing
need of the developing foetus? 1.Thinning of placental barrier
2.Margination of foetal vessels 3.Massive expansion of surface area
by arborisation What is the consequence when the placenta is not
meeting the needs of the foetus? IUGR intra-uterine growth
restriction
Slide 6
The umbilical cord.. 1. Is made up of 2 umbilical veins and 1
umbilical artery? OR.. 2. Is made up of 2 umbilical arteries and 1
umbilical vein? The second one is correct (think AVA) which carries
oxygenated blood? The umbilical vein carries oxygenated blood from
mum Whats the name of the other component of the umbilical cord?
Whartons jelly
Slide 7
List THREE factors that affect maternal fetal bloodflow 1.Fetal
heart/vessels 2.Umbilical vessels 3.Uteroplacental flow mum MCQ:
Maternal-fetal blood flow is which of the following? A.High
pressure, high flow B.Low pressure, low flow C.High pressure, low
flow D.Low pressure, high flow
Slide 8
Now for some labeling.. Of a mature placenta WORDS: chorionic
villi, placental septa, umbilical cord, amniotic membrane, smooth
chorion, umbilical vessels, decidua basalis, endometrial arteries
and veins, cytotrophoblastic shell, stump of main villus stem, main
villus stem, myometrium, and amniotic fluid. For today just name 1.
2. 4. 7. 8. 11. please.
Slide 9
What are the THREE placental functions? 1.Endocrine steroid and
peptide hormones 2.Transfer of nutrition, waste and gas exchange
3.Immunity What are the TWO peptide hormones? 1.Human chorionic
gonadotropin 2.Human placental lactogen Which one of these two
peaks at 10-12 weeks? hCG What is the role of human placental
lactogen? Glucose metabolism during pregnancy make mum resistant to
insulin. Reduced uptake of glucose into maternal cells to favour
fetal supply. What are the TWO steroid hormones? 1.Oestrogen
2.Progesterone
Slide 10
Match the molecule with the transfer mechanism! Water Amino
acids Glucose Immunoglobulins Iron Alcohol Active transport
Pinocytosis Simple diffusion Active transport Facilitated diffusion
Simple diffusion Which immunoglobulin crosses the placenta? IgG
think the placenta is gross Which immunoglobulin is found in breast
milk? IgA breast milk, areolar
Slide 11
List FOUR placenta dysfunctions 1.Position/development 2.Growth
3.Blood flow compromised 4.Transport of bad stuff eg. Alcohol What
does placenta praevia mean? Low-lying placenta example of a
positional dysfunction What are the three types? 1.Marginal
2.Complete 3.Low-lying
Slide 12
Matching up placenta problems.. What is placenta accreta,
increta, percreta? Placenta increta Placenta accreta Placenta
percreta Placenta villi invade into part of myometrium Placenta
villi invade into whole myometrium Placenta villi invade though the
full thickness of the myometrium to the serosa layer and may cause
uterine rupture. Uncontrolled invasion or abnormal attachment of
the placenta to the myometrium.
Slide 13
How can placental abruption present in a pregnant lady? Per
vaginal bleeding What are the THREE types? 1.Revealed 2.Concealed
3.Concealed and revealed
Slide 14
List THREE growth dysfunctions of the placenta 1.Uncontrolled
growth 2.Gestational trophoblastic disease 3.Molar/choriocarcinoma
List THREE blood flow dysfunctions of the placenta 1.Inadequate
placentation pre-eclampsia 2.Mechanical IVC compression 3.Volume
maternal haemorrhage, can lead to fetal growth restriction
Slide 15
Pre-eclampsia definition Failure of normal invasion of
trophoblast cells which leads to less adapted maternal spiral
arteries in the placenta this is an example of abnormal placental
development. Triad of clinical features? 1.Hypertension
2.Proteinuria 3.Oedema What is eclampsia? Tonic-clonic seizures in
pregnancy
Slide 16
What are FOUR causes of placental dysfunction? 1.Smoking
2.Drugs eg. Cocaine 3.Alcohol by what transport mechanism does this
reach the fetus? What can this cause in the fetus? Simple diffusion
moves down the concentration gradient to the fetus causing fetal
alcohol syndrome. 4. Infectious agents eg. Rubella, hepatitis B/C,
HIV
Slide 17
Thank-you! Any questions? Good luck with your revision