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Flashcards in placental and fetal physiology Deck (12)
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1

what causes villious regression, what structure forms as a result

elevated levels of oxidative stress and smooth chorion laeve formation

2

what is histiotrophic nutrition and why is it important

During early pregnancy the volume of endovascular trophoblast is such that
it plugs the mouths of the spiral arteries, preventing maternal blood flow into
the placenta. The plugging coincides with the period of histiotrophic
nutrition; Histiotroph- nutritional material in spaces between the maternal and fetal
tissues, derived from the maternal endometrium and the uterine glands.

3

what are function of placenta 4 main ones

• respiratory organ
• nutrient transfer
• excretion of fetal waste
products
• hormone synthesis

4

what happens to placental blood flow during gestation

maternal uterine blood flow increases, fetal umbilical flow increases. shows sharp rise around 30 weeks

5

where is the site of placental nutrient transport

terminal villus, fetal capillary, bm, synctiotrophoblast inbetween and microvillious membrane on the other side

6

what drives gaseous diffusion across placenta

concentration gradient

7

how are lipids transported across placenta

Lipoprotein lipase
releases non-esterified
fatty acids ((NEFAS)
from the
triglycerides in
lipoproteins (LP).
NEFAS are then transported
across the trophoblast cells
by fatty acids transport
proteins (FATP)

8

State the three systems for amino acid transport across placenta

system a, system l, taurine transporter

9

how does system a work

System A; Sodium dependent; transports small non –
essential amino acids eg alanine, glycine and serine..
Three isoforms; SNAT1, SNAT2 and SNAT4. SNAT1 major
contributor to system A activity . Regulated by cytokines
and hormones eg Insulin; IL-6 and TNFalpha and Leptin

10

how does system l work

System L; sodium independent; non essential amino
acids exchanged for essential amino acids eg leucine,
phenylalanine – enabling transport against concentration
gradient. Regulated by mTOR nutrient sensing pathway.

11

how does taurine transporter work

Taurine transporter- transport taurine against
concentration gradient- cotransport with sodium and
chloride

12

outline Glucose Transfer across the placental
syncytiotrophoblast cell

cotranported with na , Glucose transfer
predominantly
by GLUT-1 transporter in the
second
half of pregnancy ,