Changes

*Oocyte surrounded by two or more layers of follicular cuboidal cells. These cells differentiate into the inner Granulosa cells and outer Theca cells.

*Oocyte surrounded by two or more layers of follicular cuboidal cells. These cells differentiate into the inner Granulosa cells and outer Theca cells.

* Connective tissue cells surrounding the granulosa cells differentiate to form the layers of theca cells which produce androgens.

* Connective tissue cells surrounding the granulosa cells differentiate to form the layers of theca cells which produce androgens.

** Androgens act as substrates for synthesis of oestrogens by granulosa cells.

* Theca cells produce Androstienedione which is converted to [[Endocrine_System_-_Ovaries_-_Anatomy_%26_Physiology|17β-Oestrodiol ]](E2) by the Granulosa cell enzyme Aromatase.

* Granulosa cells secrete [[Endocrine_System_-_Ovaries_-_Anatomy_%26_Physiology|17β-Oestrodiol ]],

* Granulosa cells secrete [[Endocrine_System_-_Ovaries_-_Anatomy_%26_Physiology|17β-Oestrodiol ]],[[Endocrine_System_-_Ovaries_-_Anatomy_%26_Physiology|Inhibin]] and small amounts of progesterone.