Puberty Flashcards
puberty requires adequate release of GnRH, what does this hormone promote?
- gametogenesis
- steroidgenesis
- development of reproductive tissue
the tonic and surge centers are at a steady state before puberty producing GnRH, what happens after puberty?
the tonic center will continue to control slightly higher basal levels of GnRH but the surge center will now control the pre-ovulatory surge of GnRH in the female while the male will not develop a surge center
why does the surge center develop in females and not males?
In females the alpha-FP prevents E2 from crossing the BBB causing the hypothalamus to become feminized and the surge center develops
however, in the male testosterone freely enters the brain because alpha- FP does not bind it. Testosterone is aromatized into estradiol and the male brain is defeminized preventing a GnRH surge center from developing
males have small __ episodes that occur every 2 to 6 hours. Testosterone is secretes soon after each __ episode
LH
__ is a major factor affecting age at puberty that can cause __ estrus and __ milk production
Nutrition, weak, decreased
seasonal breeders such as sheep that were born in the spring would go through puberty in the __ while those born in the fall would go into puberty __
fall, NEXT fall
how does progesterone regulate the tonic release of LH to support the CL until PGF2 causes CL regression?
negative feedback
when primary follicles begin to develop __ proliferate around it to become a __ follicle which can produce small quantities of estradiol.
granulosa cells, secondary
how do antral follicles develop?
FSH acts on the secondary follicle to release follicular fluid around it and the GC’s differentiate into theca cells (becomes externa and interna) and granulosa cells
the antral follicle has the emergence of the __ follicle that produces estrogen and inhibin while the theca cells produce __ and the granulosa cells produce __
dominant, androgens, estradiol
as the H-P-G axis matures it becomes responsive to __
estrogen
theca interna receptors for LH produce __ that diffuses to FSH receptors in the __ causing the synthesis of enzymes that convert testosterone to __ which goes through the blood to the __ or __
testosterone, GC’s, estradiol, brain or reproductive tract
t/f: most follicles undergo atresia and follicular waves continue in pregnancy and during anestrus periods
T
during recruitment of follicle FSH __LH
>
during selection of follicles FSH __LH
<
during dominance of follicles FSH__LH
<, the follicle doesn’t need to grow/be stimulated by FSH anymore
what happens to the dominant follicle if there is high progesterone in the system?
it undergoes atresia
only mature follicles capable of secreting __ can ovulate
estrogen
after the preovulatory LH surge and increase in PGE2 causes increased follicular __ and wall __ which causes the pre-ovulatory graafian follucle to ovulate and become the ___
pressure, weakness, corpus hemorrhagicum
After the CH forms the theca interna and GC cells differentiate into __ cells that form the CL and produce __
luteal, progesterone
when progesterone is high, estrogen is __
low
Bovine age at puberty
11 month m/f
ovine/caprine age at puberty
7 months m/f, can vary with seasons
porcine age at puberty
m: 7 months, f: 6 months
equine age at puberty
m: 14 months, f: 18 months
canine age at puberty
male: 9 months, female: 12 months
feline age at puberty
m: 9 months, f: 8 months
