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