Question

Physiology

Answers can be explained thoroughly in jot note format or paragraphs.

Reproductive System

3. Describe the journey of the formation of a Graafian follicle starting from the primordial germ cell.  

Answer 1

Formation of a Graafian follicles

• Primodial germ cells develops from the dictyotene occytes which is suurounded by the single layer of spindle shaped flat cells pregranulosa cells.After puberty, primodial follicles undergoes folliculogenesis which is controlled by gonadotrophin homone FSH and LH.Folliculogenesis occurs through three process such as growth and maturation of the oocytes ,differentiation and proliferation of granulosa and theca cells and formation of the fluid within the follicular cavity.
• It results into formation of Primary follicle  ,here granulosa cells proliferate and undergoes differentiation process to from the cuboidal cell s from flattened pregranulosa cells.Therefore ocyte increases in size and form the plasma membrane of oocyte called as zona-pellucia.
• Subsequently ,It develops into secondary follicle . Seconday follicle contains several layer of cuboidal granulosa cells that surrounds the primary oocytes. The cells present in the ovarian stroma covers the follicle develops into theca cells and forms the basement membrane of follicle. After another differentiation ,it form two layers theca externa ,compresses the stroma and theca interna closer to the granulosa cell .These theca cells further proliferate and deveolps the LH receptors on to it.
• After that secondary follicles matures and forms the tertiary follicles. At this stage, it contains abundant amount of the granulosa cells which secretes the fluid into the central space called as antrum. Tertialry follicle has first of two antral stages and second becomes the Graafian follicles.FSH secretion facilitates the transition of the preantral secondary follicle into the antral tertiary follicles.
• As antrum enlarges, it undergoes second antral stage and follicle diameter increases further and forms the preovulatory or Graafian follicle.