Gametogenesis Oogenesis Flashcards
What is the first step of oogenesis?
The 2n Oogonium splits by mitosis into many 2n Oogonia where some grow and differentiate
When does the first step of oogenesis occur?
Before birth
What is the second step of oogenesis?
Meiosis 1 - some grow into primary oocytes all follicles
When does the second step of oogenesis occur?
After birth hours before ovulation
What happens in Meiosis 1?
The primary oocyte splits into 1n polar body and 1n secondary oocyte
What happens in Meiosis 2?
The secondary oocyte ovulates and fertilises into a 1n polar body and 1n ovum
Facts about the ovarian cycle?
Starts with 20 primordial follicles, with one reaching maturity the other regressing, Follicular, Ovulatory, Luteal
What 3 follicles are in the ovary?
Ovarian follicles - oocytes in development
Graffian follicle - Ready to rupture
Corpus Luteum - after ovulation - hormones
What is the first follicle called?
Primordial
What is the structure of a primordial follicle?
An oocyte with a layer of follicular cells, which then become granulosa cells, stromal cells keep it all connected.
What is the phase called from first to second follicle?
Preantral
What is the second follicle called?
Primary follicle
What is the structure of the primary follicle?
Increases 200-400U, synthesises mRNA, secretes glycoproteins, Forms the zona pellucida between the oocyte and granulosa cells, the granulosa cells proliferate, theca folliculi stromal cells
What is the phase called from second to third follicle?
Antral
What is the third follicle called?
Secondary follicle
