Reproductive Physiology 2 Flashcards
What does the sperm penetrate?
corona radiata
How many sperms contact the plasma membrane of the oocyte?
one
How many sperms contact the glycoprotein of the ZP and the acrosome reaction occurs which causes the ZP to be digested?
many
Fast block to polyspermy
one sperm touches the outside of the secondary oocyte causing it to depolarize
Slow block to polyspermy
first sperm will have head pulled in and the zona pellucida will harden
The male pronucleus and female pronucleus form to make?
zygote (fertilized egg)
Where does the blastocyte hatch out of?
zona pellucida
Why does the blastocyte expand?
due to fluid inside
The inner cell mass of blastocyte gives us what?
baby
The outer trophobic gives us?
fetal contribution to the placenta
Once the egg has become a zygote what happens?
divisions will occur in the uterine tube and 2 cells with become 4 because each time it divides it gets smaller because its stuck in the zona pellucida
Where does the fertilized egg enter and in what phase?
endometrium in the secretory phase
where does the egg attach to?
part of the uterus with lots of blood vessels
trophoblast eat what and invade what?
invades the endometrium and eat maternal cells for nutrition as it moves inward to build a pathway for maternal blood
Where are the first signs of development found?
inner cells
When does the amniotic sac begin development?
2 days after implementation
When does the blastocytes convert itself to the placenta?
14 days after ovulation
When does the yolk sac begin to develop and the mesoderm gets pushed out of the embryo?
after 16 days
What does the mesoderm give us?
muscles and bones
Embyronic mesoderm
- vast majority of the placenta
T/F: the thick side that is closer to the wall of the uterus becomes placenta?
true
16 day embryo: the connecting stalk becomes what?
umbilical cord
16 day embryo: What does the ectoderm make?
amniotic sac and folds over the brain and spinal cord
- makes neural tube
16 day embryo: Endoderm closes over to make what?
the gut
16 day embryo
amniotic cavity begins to develop and young sac develops where the gut will be
28 day embryo
amniotic cavity begins to completely surround the baby growing out and around the fetus
28 day embryo: What does the front of neural tube and back of neural tube become?
front- head, back- spinal cord
28 day embryo: The foregut is supplied by and is the mechanism of what?
celiac artery and endoderm closing up
28 day embryo: Hindgut is supplied by
inferior mesenteric artery
28 day embryo: midgut is supplied by
superior mesenteric artery
When does the hear begin to form?
28 day embryo
8 Weeks since fertilization: age
8 weeks- conceptual
10 weeks- biological
What are the three main phases of development
- the pre embryonic phase
- embryological phase
- fetal phase
the pre embryonic phase
- less than 14 days after fertilization
- tiny trophoblast
- zona pellucida is still present and the embryo is isolated from the maternal environment
Embryological phase
- 2-8 weeks after fertilization
- all major organs are assembled in this time
- not completed organs but basic parts
- kidneys form, heart is 4 chambers and neural tube is folded
- placenta is way larger than embryo at this point
- complete access to materials in maternal circulation
Fetal phase
- 8 weeks to term
- organs are growing during this period and become fully developed
Histogenesis phase
organs are growing
- fetal phase
Period of organogensis
organs are beginning to grow
Thalidomide
causes limb shortening in the embryological phase the limbs are made
Spina bifida
neural tube does not close in the embryological phase
- nerves wont develop normally to the pelvis and the legs
Valproic acid
convulsant drug associated with spina bifida
Microtia
tiny ears
- can be surgically reconstructed b/c its not a problem with organ development
What happens if microtia occurs in embryonic development?
no ears
Cataracts
caused by rubella which is an infectious disease
- clouding of the eye
- can be cured
What happens if cataracts occur in embryonic development?
may not have eyes
What makes up the placenta?
decidua and chorion
What is decidua?
what the mom puts into the placenta which comes from functional layer
The amniotic sac is?
surrounds the fetus
Chorion
fetal contribution to the placenta which includes the fetal mesoderm and trophoblast and amnion
Amnon
bag of fluid that formed in the embryo
Chorionic villi
- gills for the fetus
- they stick out into maternal blood to give mom waste and takes oxygen from her
The entire blood supply to fetus has to circulate through
chorionic villi
Syncytiotrophoblast
outside of trophoblast invading into the blood vessels
Cytotrophoblast
inside of trophoblast
What makes up the core of the placenta?
extraembryonic mesoderm; gives us muscle and blood vessels
Intervillous space is
where maternal blood is being flushed in and out (bring O2 and leave CO2)
Where does blood come in and what does it do?
comes in through the maternal artery and sprials in through the functionalis layer of endometrium
- then it is delivered to intervillous space
- goes in under pressure and goes back out from the endometrial venules and goes back into maternal veins and blood supply
Why does the exchange occur?
because fetal vessels are right below blood supply and fetal villi will extract oxygen out of the maternal blood
Fetal vein
picks up oxygen
Blood will
spiral down, fill up the intervilllous space, lose oxygen, gain waste products and goes out under pressure into maternal venules
Does the baby holds in breath during contractions?
yes; dont want long contractions
When does pumping of blood occur?
everytime moms heart pumps
The umbilical cord consists of
two arteries and a vein
What surrounds the umbilical cord and why?
surrounded by whartons jelly to prevent it from kinking and keep it working
Where does jelly come from?
extraembryonic mesoderm
where are the blood derivied stem cells from?
core blood
Lumen of umbilical artery
- deoxygenated blood comes in
- oxygenated blood comes out
What should happen by 3rd trimester?
extravillous trophoblast should extend deep into myometrium
Incomplete invasion is associated with and happens in what percent of pregnancies?
hypertension and 5-10%
How many maternal deaths are due to hypertension?
16%
Blood vessels have what to allow what?
smooth muscle to allow for constriction and dilation
Why do blood vessels have endothelial cells?
allows for cytotrophoblast to grow into maternal spiral artery
When does cellular immunity decrease?
maternal adaptation to pregnancy
Immunity pregnancy
- fetus is allograft
- mom has to remain tolerant to paternal antigens and maintain normal immune competence for defence
What happens if you dont inhibit maternal immune system?
immune system will wipe it out
Placenta blood requirement
- blood volume increases 30-50%
cardiac output increases
20-30%
Tidal volume increases
30-40% for mom to get rid of CO2 that the baby has
Airway resistance
decreases to increase co2 loss
What do low CO2 levels create?
stronger concentration gradient between mom and fetus
Myometrial mass increases
60-80% to accomodate the fetus
- returns after pregnancy
Progesterone is used for
- limiting contractions during pregnancy
When does estrogen increase?
end of pregnancy for contractions
Who is incharge of labour?
- fetus appears to be
- fetus will begin to make hormones (estrogen)
- stretch of uterus
- fetal pituitary secrets OT
- fetal part of placenta begins to make more progesterone prostaglandins
Ectoderm Contains
nervous system and skin
mesoderm contains
heart, blood vessels, bones, Msk ETC
Endoderm contains
Gi, Respiratory, and Urinary tracts
