lecture - pregnancy and fetal development

when does luteolysis occur

if no embryo is detected

P4 synth is stimulated by what

LH

can large luteal cells convert P4 into androgens

no they dont express the enzyme anymore

what are small luteal cells responsible for

production of androgens and estrogens

can aromatize androgens into estrogens

define fertilization

fusion between female and male gametes

no hormones req

processes leading to gamete production, maturation, ovulation, and env for embryo dev are dep on what

hormones

what ant pit hormones are critical for gametogenesis

FSH and LH

what are P4 and E critical for

prep and maintenance of uterine environment for successful pregnancy

what initiates maternal recognition of pregnancy

the embryo

what is the goal of maternal recognition of pregnancy

to extend luteal P4 by preventing luteolysis and maintain a receptive uterine environment

describe hCG

human chorionic gonadotropin

signals pregnancy to CL and keeps P4 being produced

how is pregnancy signaled in mares

physical movement

how is pregnancy signaled in cow

INF- tau by embryo

how is pregnancy signaled in sows

production of E by embryo suppressed PGF in CL preventing luteolysis

hCG is what kind of hormone

luteotropic hormone

how does hCG function

LH like activity

binds to LH receptors in CL to maintain P4 production

enters maternal blood stream

stims differentiation of cytotrophoblast to syncytiotrophoblast

when is hCG first detected

around day 9 post fert

when does hCG peak and why

peaks around 8-12 weeks of pregnancy

then CL loses function and placenta takes over for steroidogenesis

what is used for urine pregnancy tests

hCG

what are the 2 types of implantation

invasive

apposition

describe invasive implantation

fetal trophoblast invades endometrium epi

describe apposition implantation

trophoblast attaches to endometrial epi

humans have what kind of implantation

invasive

why are trophoblast cancers dangerous

super invasive

what does the synctiotrophoblast do

breaks down endometrium lining

describe the placenta

temporary organ made of fetal and maternal tissue

has endocrine function

gives physical and immune protection

allows for nutrient/gas/waste exchange

semi-permeable

what kind of enzymes does the placenta produce

enzymes that inactivate maternal hormones to control fetal exposure

what are some maternal endocrine changes during prenancy

↑ cortisol

↑ insulin

insulin resistance develops during 2nd half of pregnancy ↑ in lipolysis

↑ in RAA system

↑ aldosterone

ant pit ↑ in size

why does the ant pit ↑ in size during pregnancy

due to hypertrophy and hyperplasia of lactotrophs

what are some amternal physiological adaptions to pregnancy

↑ volume of uterine cavity

↑ blood volume

↑ plasma volume

↑ RBC count

↑ glomerular filtration rate

↑ HR, stroke vol, cardiac output

describe the maternal-fetal-placental unit

collaboration between placenta, fetal, and maternal adrenal glands to make P4 and Es needed for sucessful pregnany

what androgens are most important in pregnancy

T

androstenedione

DHEA

what Es are most important in pregnancy

estradiol - E2

estrone - E1

estriol - E3

describe DHEA

weak androgen precursor for androgen synth

what is DHEAS

DHEA + sulfate to make it inactive

does the placenta have the abiility to convert P4 to androggens

no

describe estriol

form of E only made during pregnancy due to conversion of 16α-hydroxy-DHEAS from fetal origin

what are some hormones made by placenta

P4

E

hCG

PL

what does P4 do in pregnancy

maintains pregnancy

inhibits uterine contractility

substrate for fetal synth of GCs and MCs

immunomodulation

preps mammary tissue for lactation

what does E do in pregnancy

stims uptake of LDL, VLDL, and HDL for CHO for placenta

↑ uteroplacental blood flow

maintains uteroplacental sensitivity to P4

preps mammary tissue for lactation

what does PL do in pregnancy

detected in maternal serum 20-40 days of gestation

makes sure fetus has constant supply of nutrients

similar to GH and PRL, can bind to their receptors

promoters maternal insulin resistance and ↑ lipolysis

what initiates labor

drop in P4 levels or P4 activity

what happens when there is a drop in P4 levels or activity

Ers become more abundant allowing for more prostaglandins and OT receptors to be made

cortisol levels in fetus increase

production of lung surfactant

PNMT - conversion of NE to epi

DI2 in liver - conversion of T4 to T3

NE and EPI levels in fetus increase

blood pressure and inotropic effects

glucagon/ decrease insulin secretion

thermogenesis in brown adipose

when does glucose homeostasis of a fetus normalize

within 5-7 days

when does Ca homeostasis of a fetus normalize

within 1-2 weeks

what do large luteal cells make

P4

how long does it take for a human fertilized egg to develop into a blastocyst

6-8 days

where is hCG found

blood of mother

what endocrine changes occur during pregnancy

↑ in cortisol, insulin, and aldosterone

What cardiovascular physiological changes happen in pregnancy

Blood + plasma volume ↑

RBC count ↑

Increase in HR, stroke vol, and cardiac output

Overall BP doesnt change significantly due to ↓ peripheral vascular resistance

where are the androgens of the maternal fetal unit made and converted

made in adrenal glands of mother and fetus

converted in placenta

where are the estrogens of the maternal fetal unit made

synthed in the placenta

where is P4 synth in pregnancy

synthed in the placenta

why isnt P4 conevrted to androgens in placenta

placenta doesnt have the enzymes to do it