ZOO 4605 Lecture Notes - Lecture 6: Corpus Luteum, Chorionic Villi, Marathon Trilogy
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ZOO 4605-A001
06/05/18
Syncytiotrophoblast
oPenetrates into endometrium by formation of some cisterns (spaces) and
rupture of maternal blood vessels
First step of connection between mother and embryo
Cytotrophoblast
During first trimester of pregnancy there is no complete connection between mother
and embryo
For this reason, the wall of the yolk sac gives nutrients to the embryo
During the second and third trimesters, placenta takes over giving nutrients to fetus
After formation of Syncytiotrophoblast, the first hormone which is secreted by the
primitive placenta is HCG
Gives positive signal that she is pregnancy and maintains corpus luteum which
produces progesterone
Progesterone maintains and prepares endometrium for implantation
Corpus luteum prepares and maintains endometrium for implantation
Decreases progesterone leads to abortion
Decreased prolactin also leads to abortion
Prolactin is important for preparing mammary gland for breast feeding
Most important function is suppresses FSH and LH in pregnant female so she
cannot have ovulation and menstruation
Function of placenta
Carries fresh oxygenated blood to fetus
Uptakes CO2 from fetus
oThere is no air in his lung so this small amount of CO2 is from cell
respiration
Gives nutrients, vitamins, small proteins, maternal immune cells, some
hormones,
Secretes the most important hormones during pregnancy
oHCG
oProlactin
oSmall amount of testosterone
oSmall amount of estrogen
oProduction of progesterone during second and third trimesters
oCytokines
Growth factors which are important for cell proliferation and cell
growth of fetal organs or tissues
oRelaxin hormone which relaxes pelvic cavity for pregnancy because we
need space for fetal development
Also relaxes cervix during delivery
oPrecursor of some hormones which are necessary for development of
endocrine glands
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Such as TSH which is important for development of thyroid gland
Deficiency of this hormones and maternal tithritiphore
leads to congenital hypothyroidism in newborn
s/s
Bone growth retardation
Mental retardation
Speech disorder
Motor disorder
Learning disorder
Tx
Doctor should be smart and put diagnosis on time
When they realize that future newborn may have
that disease or disorder, they must replace the t3 t4 from the
first day of his life
Hormone replacement
oPrecursor for PTH
Parathyroid hormone
Controls PT gland
Controls blood calcium which affects bone and muscle
growth,
Can cause palpitation or increase heart rate
Too much or too little is bald
Also controls some synapsis
Secreted by PT gland
oPrecursor of ACTH
Controls development of adrenal gland
Newborn may have risk for Addison's disease
Helps release cortex hormones
3 parts
Adrenal cortex (peripheral
Aldosterone
Increases blood pressure
cortisol
Anti inflammatory
Maintains blood glucose
Androgen
Female has small amount
oDecidua
The layers which develop during pregnancy
3 types
Decidua basalis
Which is between endometrium and embryonic
tissue
Decidua capsularis
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Covers the entire embryo and amniotic cavity
Decidua vera (carcialis)
Covers the entire endometrium
This layer sheds during delivery
oFormation of placenta
Formation of
primary chorionic villi
Some cells from embryo or trophoblast start to
proliferate but doesn’t reach
secondary
Reach half way
tertiary
Complete connection of endometrium
Inside villi we have capillaries which are the main structure of gas
and nutrient exchange
Arterial pressure is always higher then venous pressure
oAorta is 100 mm/mg
oVena cavas are 4 mm/mg
oSome during pregnancy
Maternal artery carries fresh oxygenated blood which releases
into placenta especially in the chorionic villi
Inside the chorionic villi, we have capillaries which up take the
oxygen and nutrients
The chorionic villi becomes the umbilical vein
The transportation of oxygen and nutrients is by simple diffusion
oMaternal arterial pressure is much higher than embryos umbilical vein
pressure
oMaterials move from higher to lower concentrated area
oUmbilical vein carries oxygen , immune cells, hormones, nutrients to
fetus
oFetal tissue uptakes all of those materials releases CO2 as a result of cell
respiration
oDeoxygenated blood is carried by 2 umbilical arteries to the placenta and
then is released into the maternal venous system
Branches of artery in placenta
oArcuate artery
oRadial artery
oBasal artery
oSpiral artery
oIntravilli space or arteries
Large molecules such as large proteins cannot cross placenta membrane
oUnfortunately alcohol and drugs can pass
Placental membrane
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Document Summary
Penetrates into endometrium by formation of some cisterns (spaces) and rupture of maternal blood vessels. First step of connection between mother and embryo. During first trimester of pregnancy there is no complete connection between mother and embryo. For this reason, the wall of the yolk sac gives nutrients to the embryo. During the second and third trimesters, placenta takes over giving nutrients to fetus. After formation of syncytiotrophoblast, the first hormone which is secreted by the primitive placenta is hcg. Gives positive signal that she is pregnancy and maintains corpus luteum which produces progesterone. Corpus luteum prepares and maintains endometrium for implantation. Prolactin is important for preparing mammary gland for breast feeding. Most important function is suppresses fsh and lh in pregnant female so she cannot have ovulation and menstruation. There is no air in his lung so this small amount of co2 is from cell respiration. Gives nutrients, vitamins, small proteins, maternal immune cells, some hormones,
