Reproduction Final Part 2 (Pozor) Flashcards
On what cells are FSH receptors found? One what cells are LH receptors found?
FSH receptors –> granulosa cells
LH receptors –> thecal cells (later on granulosa cells too)
What effects do low levels of estrogen have on GnRH, FSH, and LH? What about high levels?
Low Estrogen (-)--> GnRH, FSH, LH High Estrogen (+)--> GnRH (+)--> FSH and LH
Contrast monoestrus, polyestrus, and seasonally polyestrus.
Monoestrus –> estrus occurs once a year (wolves, foxes, bears, and dogs)
Polyestrus –> estrus occurs multiple times a year (cattle, swine, and rodents)
Seasonally polyestrus –> estrus occurs multiple times during specific seasons only (horses, sheep, and goats)
Contrast long-day breeders and short-day breeders.
Long-day breeders like little darkness. Therefore:
Long days –> Little darkness –> Little melatonin –> Estrus
Example: horses
Short-day breeders like ample darkness. Therefore:
Short days –> Ample darkness –> Ample melatonin —> Estrus
Example: sheep, goats
What hormone dominates the follicular phase? From where is this hormone secreted? What proportion of the estrous cycle does this comprise?
Estrogen
from the growing Ovarian Follicle
~20%
What hormone dominates the luteal phase? From where is this hormone secreted? What proportion of the estrous cycle does this comprise?
Progesterone
from the Corpus Luteum
~80%
Describe the four stages of the estrous cycle.
Proestrus –> High progesterone; follicles are recruited for ovulation and female tract is preparing for mating; estrogen begins to increase
Estrus –> High estrogen; mating; ovulation occurs (except for cow who ovulates at the end of estrus)
Metestrus –> Low progesterone and estrogen; formation of a functional corpus luteum; progesterone begins to increase
Diestrus –> Max progesterone; if pregnancy doesn’t occur, PGF2alpha initiates luteolysis
T/F: High levels of progesterone inhibit GnRH secretions.
TRUE
Name a hormone that inhibits FSH besides estrogen.
Inhibin
Describe lutenizing hormone (LH).
- Causes follicular maturation and ovulation
- Promotes development and maintenance of corpus luteum
- Inhibited by high levels of progesterone
Describe estrogen.
- Produced by growing dominant follicle
- Peaks around ovulation
- Responsible for sexual receptivity
- Where low levels of estrogen are inhibitory on GnRH, high levels are stimulatory, which lead to the LH surge
Describe progesterone.
- Produced by the corpus luteum
- Dominant hormone during diestrus
- Essential for pregnancy maintenance
- Inhibits estrus behavior
- Inhibits GnRH and LH
Name the enzyme that degrades and weakens the follicular wall, which leads to ovulation.
Collagenase
Which cells produce testosterone for male development? Which produce Mullerian Inhibiting Hormone?
Leydig –> Testosterone
Sertoli –> MIH
What cells prevent sperm from entering blood by creating the blood-testis barrier?
Sertoli cells
T/F: Spermatocytes are immunogenic.
TRUE
Where in the embryonic gonad of the male are the sex cords located?
In the Medulla
Where in the embryonic gonad of the female are the germ cells located?
In the Cortex
T/F: Sertoli cells divide throughout sexual maturity of a male.
FALSE
