module 7-estrous cycle Flashcards
who is considered the pioneer of hormone contraception
Dr. Wayne Bardin
what did Dr. Wayne Bardin do
developed long lasting contraception that provided an alternative to daily oral pill
what is Mirena? when was it FDA approved?
-an intrauterine device that releases a progesterone agonist(levonorgestrel)
-FDA approved in 2000
hormones used in cosynch method, and their purpose
-GnRH: induce follicular waves/growth, induce ovulation
-Prostaglandin: regress CL
-CIDR(progesterone): Blocks ovulation
timeline for cosynch method
-Day 0: GnRH injection, insert CIDR(grows new dominant follicle)
-Day 7: remove CIDR, give prostaglandin injection
*day 7: Place estrotect patch
and moniter for estrus(2-3
days)
OR
*Day 9: give GnRH injection and AI
method for estrus synch in pigs
feed matrix for 14 days, then expose to boar, then breed
what is prostaglandin secreted by
the uterus
how does prostaglandin get to the ovary
counter-current exchange to ovarian artery
does prostaglandin go through a counter-current exchange in horses? why/why not?
no, prostaglandin is not metabolized as well in horses so there is still enough left after traveling through the body to regress the CL
division of estrous cycle based on ovarian structures
-follicular phase
-Luteal phase
division of estrous cycle based on hormone profile
-proestrus
-estrus
-metestrus
-diestrus
follicular phase traits
-dominant structure
-dominant hormone
-start
-end
-relative length
-dominant structure: follicle
-dominant hormone:estradiol
-starts with luteolysis
-ends with ovulation
-30% of cycle
luteal phase traits
-dominant structure
-dominant hormone
-start
-end
-relative length
-dominant structure: CL
-Dominant hormone: progesterone
-starts with ovulation
-ends with luteolysis
-70% of cycle
proestrus traits
-2-3 days
-increase estradiol
-decrease progesterone
estrus traits
-24 hours(approximately)
-peak estradiol
-LH surge
metestrus traits
-5 days
-decrease estradiol
-increase progesterone
diestrus
-longest phase
-peak progesterone
polyestrus
display estrus throughout the year
seasonally polyestrus
display more than one estrus cycle during specific time of year
monestrus
display estrus once a year
Ex: bear, foxes, dogs
what animal is in constant estrus
rabbits
length of menstrual cycle
28 days
what is the start of the menstrual cycle
menses
phases of menstrual cycle
-menses(CL regression)
-proliferative(rebuilding what was sloughed off)
-secretory
agonists for estradiol
ethynyl estradiol
mestranol
agonists for progesterone
norethindrone
levonorgestrel
anestrus
no ovarian structures(not cycling)
start of estrus cycle
ovulation
proportional length of luteal and follicular phase in menstruation
50/50 split
length of menses
2-5 days
who was the last northern male white rhino, when did he die?
Sudan, 2018
what is the possible hope for northern white rhinos
two viable embryos were produced that will likely be carried by southern white rhinos
parts of the follicle
-granulosa cells
-theca cells
-follicular fluid
-oocyte
theca cells
-from stroma
-respond to LH
-convert cholesterol to testosterone
granulosa cells
-from cortex
-respond to FSH
-convert testosterone to estrogen
jobs of FSH
-granulosa cell mitosis
-increase LH receptors
-Steroidogenesis
-effect preantral and antral follicles
jobs of LH
-steroidogenesis
-effect antral follicles
-surge starts ovulation
-resume meiosis
gonadotropin independent
-initial development of follicle growth
-primordial—>primary(preantral)
gonadotropin responsive
-follicle can respond to gonadotropins but its not required(antrum formation)
gonadotropin dependent
removal of gonadotropins results in atresia(tertiary and on)
initial follicular recruitment
recruited from primordial follicle pool (gonadotropin independent)
cyclic follicular recruitment
antral follicles recruited towards ovulation during specific estrous cycle(gonadotropin dependent)
how many follicular waves occur throughout the estrous cycle
2-4
what gonadotropin are dominant follicles more dependent on
LH and E2
what gonadotropin are selected follicles more dependent on
FSH
Selection phase
-number selected
-hormone profile
-1 follicle for single bearing, more for litter bearing
-decreased FSH, LH dependence
recruitment phase
-number selected
-hormone profile
-many follicles recruited
-increased FSH
dominant phase
-number selected
-hormone profile
-selected follicle becomes dominant
-estrogen and inhibin(prevent FSH production)
