OOGENESIS FOLLICULOGENESIS GRAAFIAN FOLLICLE.pptx

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1. OOGENESIS

2. Process of formation of female gamete “ ovum ” Starts in fetal life, ends at “ menopause ”

3. PRIMORDIAL GERM CELLS (OOGONIA) (Migrate from yolk sac 6 th week of gestation) OOGENESIS MITOTIC DIVISION OOGONIA (7 Millions) PRIMARY OOCYTES (46) MEIOTIC DIVISION I (fetal life, 8 th week) (Meiotic arrest in prophase ) SECONDARY OOCYTES (23) MEIOTIC DIVISION II (at fertilization) (Meiotic arrest in prophase ) OVUM SECOND POLAR BODY FIRST POLAR BODY

4. FOLLICULOGENESIS

5. Growth and development of “ matured follicle - containing ovum ” from “ primordial follicle ”

6. “ Four ” stages Stage I : Primordial follicular stage Stage II : Primary follicular stage Stage III : Secondary follicular stage Stage IV : Tertiary follicular stage

7. FOLLICULOGENESIS

8. Stage I : Primordial follicular stage Consists “ primary oocyte (25µm) ” Flattened “ pregranulosa cells ” Enters to “ meiosis I ” Arrested in “ prophase ”

9. Stage II : Primary follicular stage Formed from “ primordial follicle ” “ Cuboidal granulosa cells ” “ Oocyte ” ( 80-140 µm ) Forms “ zona pellucida ” layer

10. Stage III : Secondary follicular stage Primary follicles to “ secondary follicles ” 500 µm Development of “ antrum ” – “ preantral follicle ”

11. Stage IV : Tertiary follicular stage Final stage Two sub divisions 1. Early tertiary or antral follicular stage 2. Late tertiary or Graafian follicular stage “ 20 mm ”

12. GRAAFIAN FOLLICLE