Oogenesis + Ovulation Flashcards
oogenesis
- production of immature eggs in ovaries of fetus
- complete by time of birth
female reproductive lifetime
- describes years when mature eggs are released
- from puberty to menopause
menopause
end of reproductive lifetime (at ~50 yrs old)
oogonia
female egg stem cells
process of oogenesis (2 steps)
- oogonia undergo mitotic division –> 2 primary oocytes (daughter cells)
- primary follicles cover the primary oocytes
egg maturation overview
- begins at puberty
- a few follicles mature each month
- caused by release of follicle stimulating hormone (FSH) by ant pit. gland
egg maturation process
primary oocyte in follicle undergoes meiotic division, producing secondary oocyte + polar body
polar body
contains same chromosomes as secondary oocyte but donates its cytoplasm to oocyte (important in case oocyte becomes fertilized)
secondary oocyte
- mature egg that is released during ovulation
- if not fertilized, leaves body via menstruation
if secondary oocyte unites with sperm
- the now fertilized egg undergoes another meiotic division
2. this produces an ovum (which forms zygote w/sperm) + a second polar body
zygote
- fertilized egg
- made up of ovum (23 chromosomes) and sperm (23 chromosomes)
ovarian cycle
~ every 28 days ovulation occurs
ovulation
- release of mature egg (secondary oocyte) from ovary
- triggered by release of luteinizing hormone from ant. pit gland
corpus luteum
- what ovarian follicle turns into once its egg has been released
- helps maintain pregnancy if egg becomes fertilized (disintegrates if not)