Folliculogenesis Flashcards
what is folliculogenesis
process of follicles devolping
where does folliculogensis occur
on the ovary (cortex)
what does each follicle contain
an oocyte (1:1 ratio)
in equine where does folliculogenesis occur
in the center of the ovary (medulla)
females are born with a finite number of what
eggs and follicles
what are primordial follicles
- single layer of squamous shaped follicular cells that surround oogonia
- only see oolemma
once an oogonia is surrounded by follicular cells, what no longer happen
mitosis, so then enters meiosis
when females are born, what phase are their oocytes in
prophase 1
what is a primary follicle
single layer of cuboidal cells
cuboidal cells=
granulosa cells
can the primary follicle regress into the primordial follicle
no, can only stay as is or move forward
secondary follicle characteristics
- has multiple layers of granulose cells
- see emergence of theca cells
- formation of zona pellucida
what forms in the antral follicle
antrum
antrum
- fluid filled cavity
- gets larger over time
granulosa cells surround egg itself
cumulus cells
what hormone binds to theca cells
LH
what hormone binds to granulosa
FSH
what hormone do the theca cells make
testosterone
job of 17a-hydroxylase and 17,20 lyase
convert progestogens into androgens
after FSH binds, what does granulosa produce
estradiol
bigger the follicle…
the more estradiol made
smaller the follicle…
the less estradiol made
where does the estradiol go back to
targets brain and reproductive tract
what do the number of follicles made depend on
species
monotocous
- one offspring
- 1 egg
- 1 follicle
- 1 ovulation
example of monotocous species
horse
polytocous
- little bearers
- multiple follicles ovulate at once
example polytocous
swine
gonadotropin independent growth
- prenatal (before puberty)
- don’t depend on LH and FSH
- up until secondary follicles
gonadotropin dependent growth
- antral (after puberty)
- need LH and FSH
dominance
- large follicles
- may die or move on
- final growth of ovulatory follicles
where does recruitment, selection, and dominance occur
antrum
recruitment
- small follicles
- entry into gonadotropin
selection
- medium follicles
- ovulatory follicles emerge
FSH dependent
recruitment
selection
LH dependent
selection dominance
when is estradiol positive feedback
recruitment when follicles are small
what produces inhibin
granulosa cells
inhibin job in females
inhibits release of FSH
when does inhibin pop up
selection and dominance
