reproduction 3 - fertilization, pregnancy, lactation Flashcards
what is fertilization
fusion of the male and females gametes to form a zygote
when is it called an embryo
first 2 months
when is it called an fetus
after 2 months
where is the site of fertilization
female oviduct
how many long is sperm viable for
5 days
how long is oocyte viable for
12-24 hours
what must happen to sperm for it to be able to fertilize
capacitation
what are 2 reasions that only a few hundred sperm make it into the uterine tubes
acidic tract and leakage from cervis
how many sperm go into vagina
2X10^8
how many sperm go into uterus
100 000
how many sperm go into ampulla (near end of fallopian tube)
100
what layer of the graffian follicles do the acrosomal enzymes digest
the zona pellucida
what causes the block to polyspermy (3)
corticol granules release stuff which causes the hardening of the zona pellucida and enzyme inactivate the sperm binding receptor
what happens to the oocyte once the sperm fuses
2nd meiotic division so it becomes an ovum
what happens to the sperm membrane once the sperm fuses
disintergrates
which days is it a morula
3-4 days
what does totipotent mean
all necessary info is there that is needed to create a full fetus
which cell stage are the totipotent
16-32
what is cell cleavage like in morula
mitosis but no increase in overall size
what stage of embryo can they reach the uterus
morula
is the morula totipotent
yes each cell is totipotent
what happens when the totipotent morula cells split
identical twins
what happens with fertilization of two oocytes
non idtentical fraternal twins
does the blastocyst have a zona pellucida
no (it is replaced by trophoblast)
what is trophoblast
the outer cell layer
what does the trophoblast become later
fetal placental
what will the inner cell mass of the blastocyst become
the embryo
are blastocysts totipotent
no
what days is blastocyst post fertilization
4-5
what is the blastocoele
fluid filled cavity of the blastocyst
how many days post fertilization does implantation happen
6-7
what allows the blastocyst to implant
the sticky tropoblast cells
what is the decidual response
when the blastocyst anchords and embeds itself into the endometrial wall
what will the amniotic cavity become
housing for the new fetus
in how many weeks is the placenta functioning and heart beating in child
5 weeks
what is the role of amniotic fluid
buffer / cushion for fetus
why do the sinus and chorionic villus come in contact
they dont! the chorionic villus prevent blood contact
what does the sinus contain
the mothers blood
where do the chorionic villus protrude into
the sinus where exchange can occur
is placenta endo or exocrine
endo
what does placenta exchange for fetus
respiratory gases, nutrients and waste products
do B and T cells go through the placenta
no
which hormone maintains the corpus luteum
hCG
when does hCG spike
60-80 days post fertilization
why does estrogen and progesterone constantly rise post fertilization
because corpus luteum remains due to hCG
what does hCS look like in graph
it mimics the pattern of E and P but higher
does hCG or hPL/hCS rise first
hCG
what is the main role of hCG
maintains corpus luteum in early pregnancy
why is hCG important in early pregnancy
the placenta has not taken over its endocrine role
what is the role of hCS/hPL
GH-like and anti-insulin in mother so the fetus can have more glucose
which hormone contributes to maternal gestational diabetes
hCS/hPL because it is anti-insulin like
what are the 4 major hormones of the placenta
hCS/hPL
hCG
P
E
when is progesterone made in the pregnancy
mid-late once the corpus luteum slows
what does progesterone do to LH and FSH
inhibits (you want dormant ovaries)
what does progesterone do to uterine contractions
decrease
what does progesterone do to alveolar glands
growth
what does progesterone do to mucuous
makes it sperm unfriendly
what does estrogen do to uterus
grows myometrium
what does estrogen do to LH and FSH
inhibit
what does estrogen do to mammary ducts
growth
what does estrogen do to oxytocin sensitivity
increase (makes more receptors)
is P or E dominant when it comes to contractility
progesterone (supresses it)
where is cholesterol made into progesterone
in the placenta
where is progesterone made into androgens
in the fetal adrenal glands
where is androgens made into estrogen
in the placenta
where is oxytocin secreted
posterior pituitary
when does oxytocin do to uterine contractions
increase/ strengthen
what causes the oxytocin to increase
pressure of fetus against cervix
what 4 things increases myometrial contractions
E, Prostaglandins, oxytocin, stretch
what 2 things inhibit myometrial contractions
progesterone and relaxin
what 2 things increases cervical ripening
prostaglandins sand relaxin
what decreases cervical ripening
progesterone
where does relaxin come from in humans
corpus luteum
where does relaxin come from in animals
placenta
what is cervical ripening
softens tissues cervix and allows bones to move apart
what is the order of the things in the mammary gland
alveoli in lobules makes lobes which lead into ducts
what are the mammary glands like from birth to puberty
very few alveoli, rudimentary ducts
what are the mammary glands like at puberty
ducts grow and branch out, some alveolar growth, deposit fat and alveolar tissue
which hormone causes ducts to branch out and grow in puberty
Estrogen
which hormone causes alveolar growth in puberty
Progesterone
what does prolactin do
lactogenesis
what causes prolactin release
low E and P
what hormone is required for milk ejection
oxytocin
what hormone is required for milk let down
oxytocin
what are myoepithelial cells
epithelial cells with muscle like (contractile) properties
where does oxytocin act on
receptors on myoepithelial cells
how do myoepithelial cells help with milk ejection
oxytocin triggers them to squeeze milk out of the alveolar cells
is the suckling reflex positive or negative
highly positive
what does dopamine do to prolactin
decreases it
what does suckling reflex do to dopamine (PIH)
decreases
what is milk let down
milk ejection
