Meiosis, fertilization, implantation, infertility Flashcards
Two key functions of the ovary and testicles
1) Generation of GAMETES with full competence
2) Secretion of STEROID HORMONES required for SPERMATOGENESIS and for preparation of the female reproductive tract to allow fertilization and subsequent establishment of pregnancy.
When a sperm comes into close proximity to an egg, it undergoes hyperactivation. This means the sperm can no longer move forward, instead it just propels itself inside the zona pellucida of the egg. Any inflammation inside the female tract can catalyze this process before the sperm gets to the egg and the sperm loses the ability to move forward and dies.
ok. This is how IUD’s work
Functional unit of the ovary?
follicles
Eggs come from the yolk sac
ok
Time of maximum apoptosis regarding eggs?
20 weeks gestation until birth
How many eggs at 20 weeks?
7 million
How many eggs at birth
2 million
How many eggs once puberty starts
Half a million
How many eggs at menopause
1,000
For every egg that undergoes ovulation, how many eggs undergo apoptosis
1,000
Primary oocytes begin Meiosis I during fetal life, when do they complete it?
Primary oocytes complete meiosis I just before ovulation occurs.
What happens to the Primary Oocytes that prevents them from completing Meiosis I prior to birth?
They are halted in Prophase I of Meiosis I until ovulation.
Once prophase 1 occurs, what happens to the Primary oocytes?
They divide into two things:
1) a secondary oocyte and a polar body which can degenerate or give rise to two polar bodies.
At the point in time where the primary oocyte undergoes Meiosis I prior to ovulation, what is the name of the follicle?
Graffian Follicle…..remember 1 follicle for 1 egg and vice versa
The secondary oocyte, derived from the completion of meiosis I does what?
Is halted at metaphase in Meiosis II until fertilization.
