The dark purple cells are the granolosis cells and the light purple cells are the Fegus cells and these two cells have different functions. Now the follicle stimulating hormone actually stimulates the differentiation and the proliferation of the granulosa cells while the luteinizing hormone stimulates differentiation and the proliferation of these FECA cells. And what these two cells do is they work together to form a hormone known as estrogen. So theca cells use cholesterol to form androgens and then they release those androgens and give the androgens to granulosa cells. And the granalosa cells contain a special enzyme that is capable of transforming the androgens produced by FECA cells into estrogen. Now once they produce estrogen the estrogen basically does several things.