Final answer:
Granulosa layer differentiation occurs during ovarian follicle development. It involves the proliferation and transformation of granulosa cells followed by luteinization after the LH surge. This process is vital for estrogen and progesterone production and the regulation of the ovarian cycle.
Step-by-step explanation:
The differentiation of the granulosa layer is a crucial aspect of ovarian follicle development. After puberty, primordial follicles develop into primary follicles characterized by a single layer of granulosa cells. These cells transition from a flat shape to a cuboidal shape, proliferating as they grow. Follicles then become secondary follicles, expanding in diameter and forming additional layers like connective tissue, blood vessels, and theca cells, which collaborate with granulosa cells in estrogen production.
Upon the LH surge, the granulosa cells undergo luteinization, transforming the collapsed follicle into a corpus luteum which produces progesterone, essential for pregnancy establishment and maintenance. The corpus luteum also initiates negative feedback to prevent the development of new dominant follicles. The number of granulosa and theca cells, responsive to LH stimulation, dictates the amount of estrogen produced, influencing which follicle becomes dominant.