Importance of Placenta Flashcards
what cells do foetal part of placenta mostly develop from
trophoblast cells of embryonic blastocyst
what do trophoblast cells invade (2)
- decidua (maternal uterus)
- including spinal arterioles
what does trophoblast invading spinal arterioles do
initially block maternal flow into placenta
what does the initial block of maternal flow cause early placenta environment to be developing in
hypoxic environment
consequence of exposure to higher O2 concentrations for developing placenta
impairs placental development
what are chorionic villi
nutrient exchange units of placenta
the chorionic villi containing foetal capillaries are bathed in maternal blood by when
second trimester
during second trimester at what volume (general) is maternal blood flow occurring and at what velocity (general)
- high volume
- low velocity
how are functions of placenta increased overtime
adaptations are made
is the rate of placental growth constant throughout pregnancy
no, slows down
remodeling of maternal blood vessels involves what
- expanding their diameter
- removing muscle layers that would constrict capillaries (as they do in other maternal vascular beds)
in second or later pregnancy, how does the weight of placenta compare to those in first pregnancy
heavier
does parity or offspring sex have a bigger effect on placenta weight
parity
what makes up placental efficiency ratio
foetal weight to placental weight
what can low ratio of placental efficiency indicate
poorly functioning placenta that does not effectively transfer nutrients to foetus
are foetal weight and placental weight positively or negatively correlated (in general, full-term babies)
positively
what is having a light placenta associated with
poor foetal growth
(born small for gestational age)
for poor foetal growth (ie/ growth restricted) babies due to poorly functioning placentas (ie/ light placenta), how was O2 delivery
reduced
is O2 higher in umbilical vein or umbilical artery
umbilical vein
blood of umbilical vein route
from placenta to foetus
blood of umbilical artery route
foetus to placenta
light placenta is also associated with increased risks of
still birth
placental measures of are also predictive of what
- poor personal health in offspring
what happens to placental growth in late pregnancy although foetus is still growing rapidly
slows
in normal pregnancy does foetal growth become restricted, why / why not
- restricted by placental capacity to deliver nutrients
what predicts the weight of newborn baby
placental weight and function
poor placental growth and function restrict (?) and increase risks of (2)
- restrict foetal growth
- increase risks of still birth and poor health of offspring
(4) major functions of placenta
- nutrient, gas, waste exchange
- hormone production
- protection from environment (toxins, pathogens)
- immune protection
what is the importance of the placenta for mother
placental signals are essential to coordinate maternal adaptations to pregnancy
what do maternal adaptations to pregnancy allow regarding placenta
- mothers body to supply O2 and nutrients & remove wastes from foetus via placenta
list a maternal adaptation to pregnancy that is preparative
- facilitating changes that prepare for supporting newborn thru lactation
what are some hormones produced by the human placenta
- steroid hormones (incl progesterone)
- human chorionic gonadotropin
- placental lactogens
- growth hormone
