Flashcards in Lecture 06: Female Reproductive Cycle (Kelleman) Deck (45):
reproductive cycle of non-primate species. Period from one estrus to the next.
2 phases of estrous cycle
follicular and luteal
estrous vs. estrus
estrous refers to the cycle, estrus refers to period of behavioral receptivity during the estrous cycle
Monoestrous and species
one estrous cycle per year. Wolves, foxes, bears, most dogs
polyestrous and species
repeated estrous cycles are uniformly distributed throughout the year. Cattle, swine, rodents
seasonally polyestrous and species
repeated estrous cycles for a PORTION of the year. Horses, sheep, goats, cats
any time period when the female is not cycling
cyclicity of seasonal breeders is determined by which environmental factors? What hormone do these factors directly influence?
photoperiod and temperature. Regulates melatonin secretion
More melatonin is produced in darkness or light?
what produces melatonin?
pineal gland. It is an indoleamin hormone
Short-day breeders and species
cyclicity occurs during fall months, give birth in spring. Sheep, goats
melatonin stimulates or inhibits GnRH secretion in short day breeders? ****
Long-day breeders and species
cycle in spring/summer and give birth in spring. Horses
melatonin stimulates or inhibits GnRH secretion in long day breeders? ***
What does melatonin act on?
What hormone does hypothalamus release (in reference to cyclicity)?
What does GnRH act on?
What hormones are released by pituitary gland (in reference to cyclicity)
What do FSH and LH act on?
What is reproductive cyclicity driven by?
secretion of hypothalamic and pituitary hormones
How is progesterone used clinically?
used to make fake CL and keep animal out of heat
luteolysis (killing off CL)
FSH, LH, and inhibin are included in which class of hormones?
(released by hypothalamus) stimulates synthesis and secretion of LH and FSH from anterior pituitary gland
(released from AP) promotes follicular development in the female.
(released from AP) causes final follicular maturation and ovulation. Promotes development and maintenance of CL
What hormones inhibit FSH?
What hormone inhibits LH?
Where is estrogen produced? Fx?
Produced in ovarian follicles.
-Causes estrous behavior, ONLY when progesterone is low.
-High lvls cause GnRH and LH surge
Where is progesterone produced? Fx?
-Inhibits estrous behavior
-Inhibits GnRH, LH
Where is prostaglandin produced? Fx?
-Causes destruction of CL
Decreasing Prostaglandin --> GnRH
Which estrous phase has high progesterone?
Which estrous phase has high estrogen?
In which phase of estrous cycle does ovulation occur?
2 subdivisions of follicular phase
Proestrus and estrus
2 subdivisions of luteal phase
metestrus and diestrus
Main events of proestrus
1) declining progesterone, rising estrogen
2) 3rd wave of follicles recruited, dominant follicle selected but doesn't ovulate yet
3) female attracts male but doesn't allow mating
Main events of estrus
1) high estrogen, low progesterone
2) ovulation of dominant follicle occurs
3) female receptive and mating occurs
Main events of metestrus
1) declining estrogen, rising progesterone
2) CL forming
3) female not receptive
4) 1st wave of new follicles recruited, but does not reach ovulation because of high progesterone
Main events of diestrus
1) High progesterone, low estrogen
2) 2nd wave of follicles recruited, ovulation not reached because of high progesterone
3) female refuses male
luteolysis and when it occurs
when no pregnancy, prostaglandin released by endometrium and CL destroyed. Occurs at end of diestrus
Order of estrous cycle phases
Proestrus --> estrus --> metestrus --> diestrus "PEMD"
How do rising lvls of estrogen feed back to surge center of hypothalamus? ***
Positive feedback loop. Estrogen --> GnRH --> LH --> ovulation and spinofollicular maturation