OOGENESIS
DR.SHABANA ALI
FEMALE REPRODUCTIVE SYSTEM
INTRAUTERINE LIFE
2nd wk..yolk sac
5th wk…gonades
3rd_5thmonth
..mitosis
7thmonth..
degeneration
40,000 at birth
500 ovulation,
One oocyte is released in each cycle
INTRAUTERINE LIFE
Primordial follicle
meiosis I
(prophase)arrest
AT PUBERTY
Monthly ovarian cycle
Primary follicle Secondary follicle
Secondary oocyte,
One polar body.
(ovulation)if fertilization occur
mature ovum,polar bodies
Resum
e
Meiosis one complete
2nd meiosisMetaphase arrest
Meiosis 2 completes
Intrauterine life
Primordial follicle
At puberty
Primordial follicle
Primary follicle
Secondary follicle
Primary oocytes Secondary oocyte
Ist meiotic divison till prophase
.Complets Ist meiotic division
.Starts 2nd meiotic division till metaphase
• Every month,15-20 follicles are selected and they mature in three stages
• 1.primary/preantral
• 2.secondary/antral-longest
• 3.preovulatory-37 hrs before ovulation
INTRAUTERINE LIFE
PRIMORDIAL FOLLICLE1.Primary oocyte2.flat cell layer
PRIMARY FOLLICLE
1.granulosa cells..stratfied cuboidal cells2.zona pellucida..Acelluler,glyco protein layer,impermeable3.theca folliculi…theca externa and interna
SECONDARY FOLLICLE1.Antrum2.cumulus oophorus3.size-increased4.25mm in size
CORPUS LUTEUM1.cell number increased2.vascularity increased3.size… more than 25mm
CORPUS ATRETICUM1.cell number decreased2.vascularity decreased3.degeneration
CORPUS ALBICAN
1.Fatty degeneration of cells2.Fibrous tissue
Gonadotropins, Hormones, and the Ovarian and Uterine Cycles
Pituitary-Ovarian Axis
oogenesis