When placenta grow at the fastest pace
1st half of pregnancy
Placenta is needed for
-Organ, which is a mix of both tissues: Interface between microcirculatory systems of mother & fetus, but 2 blood supplies do not meet
- Exchange of nutrients, respiratory gases, metabolic waste, protection of fetus,
source of hormones.
what is the name of the cells that connect mother and fetus
-Cytotrophoblasts,
How exchange in placenta occurs
Exchange of oxygen and nutrients take place as the maternal blood flows around terminal villi in the intervillous space.
The in-flowing maternal arterial blood pushes deoxygenated blood into the endometrial and then uterine veins back to the maternal circulation. The fetal-placental circulation allows the umbilical arteries to carry deoxygenated and nutrient-depleted fetal blood from the fetus to the villous core fetal vessels. After the exchange of oxygen and nutrients, the umbilical vein carries fresh oxygenated and nutrient-rich blood circulating back to the fetal systemic circulation.
how the branching from umbrical arteries happen
-Arteries divide radially -> branch into the chorionic plate -> villi.
function of amniotic fluid
Amniotic fluid: shock absorber & prevents dessication of fetus, provides room for
fetal movements & assists in body temperature regulation.
The smaller the palcenta, how it will impact the weight of the child
Lower the weight
urination of the fetus happens where
in the amniotic fluid
NTD sample is taken from ___ to check the presence of
in amniotic fluid to check that Alpha-fetoprotein is not high
Major functioning unit of the placenta is and fetal portion of placenta is called
Chorionic villus
Chorion
In addition to metabolism what other functions placenta has
metabolism (synthesis of glycogen, lactate, cholesterol)
what compounds can pass in placenta
large MW molecules cannot cross
Many drugs, Oxygen diffuse across placental membrane by passive diffusion.
Fetal Hb has greater binding capacity for oxygen. ( and if mother is smoking binding CO)
Passive immunity ( antibodies can come through placenta)
What substances are transported by passive diffusion
Oxygen, CO, FAs, steroids, electrolytes, fat soluble vitamins
faciliated diffusion of what substances occur in the placenta
Sugars (as a protective mechanism form mother's hyperglycemia, because extra glucose will cause non enzymatic glycation and will be teratogenic) and LCFAs (PUFAs)
Active transport in placenta occurs for what substances
Amino acids (needed for growth), some cations (Ca, Fe,I, PO4), water-soluble vitamins: energy-dependent active
transporters
folate is transported via ___ through placenta
pinocytosis
How much glucose and oxygen placenta takes up itself
50% of oxygen and 65% of glucose of maternal blood
water and solutes are transported by
solvent drag (osmotic pressure)
why sifficient Fe intake is importnat in the first half of pregnancy
So, placenta grows to sufficient size
( int he first half of pregnancy placenta grows faster than fetus)
but in 3rd trimester, fetus doubles in size when placental weight increases only by 50%
influence of maternal malnutrition on the placenta
maternal cardiac output increases during pregancy, but if not sufficient increase, then bad
What happens with nutrient transported through placenta in last 4 weeks
progressive decline in quantity of nutrients transferred/unit fetal body mass/unit time->partial responsible for fetal growth deceleration
that is why if gestation is more than 40 weeks, maybe declien in weight, because placenta can not provide enough oxygen
What chemicals cna increase placenta blood flow
Prostaglandins (vasodilation)
That is why PUFAs are needed (precursors)
Why placenta can fail its function ( failure of uteroplacental blood vessels)
Severe mother hypertension, renal diseasse, placental infraction
EFA deficiencies->defects in placental integrity and function ( no hormones that keep patency of the placenta and membrane integrity)
Low concentration of EFA will lead to
Short gestation and small head circumference
better EFAs status will show ___
better cognitive developement
leukotriens are also important
Fish intake has been associated with
better cognitive development ( lipids: 50-60% of brain structural matter)
omega 3 -21% and omega 6-15%
Function of placenta ( apart from exchange)
- -human chorionic gonadotrpin (maintains corpus luteum which secretes estrogen &
progesterone)
2. Human placental lactogen: produced in late gestation. Influences fat and CHO
metabolism. Breaks down maternal fats for fuel.
3. -Progesterone: by corpus luteum until 10 weeks placenta takes over.
-Inhibits secretion of pituitary gonadotropins (LH and FSH) to prevent
ovulation and supports the endometrium
-Suppresses contractility in uterine smooth muscle.
4. Estrogen: maximal toward end of gestation.
-Stimulates myometrium growth, antagonizes myometrial-suppression by
progesterone, stimulates mammary gland development
5. Hormone metabolism (-Glucocorticoids, insulin & thyroxine access to fetal tissues largely controlled by
placenta (metabolized to inactive forms)
6. Nutrient storage
7. limited protection against xenobiotics, becauses permeable to a lot of substances
When peak of HcG and who secretes it before placenta
-Secreted by blastocyst on day 7. After implantation, produced by placenta, peak
between the 10th & 11th.
What physiological changes happen during pregnancy and when
first half of gestation
- In most cases, the physiological activity increases, apart from the smooth muscle function of the uterus (to prevent contractions) and the smooth muscle function of the GI tract (to prevent heartburn).
What adaptations happen during pregnancy in kidney?
