Fertile Female Flashcards
what is the female germ cell
oocyte
what are the stages of oogenisis
primordial germ cell undegoes meiosis (before birth) to make a primary follicle
meiosis is halted
At puberty: forms follicle by associating with stromal cell
meiosis is completed and 1st polar body is formed
2nd meiosis starts - produces mature follicle
ovulation
what cells regulate oocyte development
granulosa cells
what is the function of Theca cells
line follicle preventing blood from entering (prevents WBC from phagocytosing oocyte
describe the structure of a Graafian (mature) follicle
inner oocyte
has follicular fluid
internal granulosa cells
surrounded by theca cells
what protects the oocyte in a follicle
zona pellucida made of glycoproteins
what is the function of follicular fluid
increase follicle size for ovulation
what triggers granulosa cell proliferation
Theca cell bind to LH
why do granulosa cells proliferate
secrete oestrogen
bind to LH - which triggers more oestrogen release
which causes even more proliferation
Describe the stages of ovulation of menstruation
- GnRH released from hypothalamus causes surge in hypothalamus (puberty)
- triggers LH surge
- meiosis resumes in oocyte
- granulosa cells loosen from zona pellicuda
- blood flow increases to follicle (increasing size)
- granulosa cells stop producing oestrogen and start producing progesterone
-oocyte leaves follicle (ruptures) as Corpus Hemorrhagicum - passes down uterine tube
- develops to corpus luteum
- some granulosa cells remain around oocyte as corona radiata
corpus luteum secretes progesterone (inhibits GNRH secretion)
what is the name of the ruptured follicle
corpus hemorrhagicum
what happens to left over granulosa cells (that dont form corona radiata)
become large luteal cells
what happens to left over theca cells after follicle rupture
become small luteal cells
name the stages of the oestrous cycle
Pro-oestrus
Oestrus
Dioestrus (metoestrus)
Anoestrus
what hormone is dominant during the pro-oestrus stage
oestrogen
what is the oestrus stage
female allows itself to be mated ‘heat’
what hormone is dominant in the Dioestrus stage and why
progesterone so is no longer fertile (corpus luteum development)
what is the Anoestrus stage
period between cycles with little/no ovarian activity
what type of oestrus cycle do dogs have
monoestrus (1 per year)
what type of oestrus cycle do horses have
seasonally polyestrus
what type of oestrus cycle do cows have
polyestrus
what occurs during the luteal phase
ovum travels to the uterus
if no fertilisation, leutolysis occurs:
PGF2a produced which trigger large luteal cells to synthesise oxytocin
causes vasoconstriction of corpus luteum so it dies
Does progesterone stop follicle development?
no
how does follicle recruitment and development work in animals that have multiple offspring?
many follicles recruited and selected, then many can become dominant
