Final answer:
Follicular cells, also known as granulosa cells, are located in the ovarian follicles and play a crucial role in the maturation of oocytes and the production of estrogens, supporting the menstrual cycle and reproductive health.
Step-by-step explanation:
Follicular cells, also known as granulosa cells, are specialized cells found within the ovarian follicles. After puberty, each day a few primordial follicles respond to a recruitment signal and start the process of folliculogenesis, maturing into primary follicles. Initially, primary follicles possess a single layer of flat, squamous-shaped granulosa cells, but as folliculogenesis progresses, these cells become active, transition to a cuboidal shape, proliferate, and form multiple layers surrounding the oocyte.
This transitional phase leads to the formation of secondary follicles, characterized by a primary oocyte surrounded by multiple layers of granulosa cells and a new outer layer of connective tissue, blood vessels, and theca cells, which synergize with granulosa cells to produce estrogen.
The process is key for reproductive health as these cells provide nourishment and hormonal support to the developing oocyte, contribute to the formation of the zona pellucida, and are vital for the production of estrogens, which are essential for the development of secondary sex characteristics and the regulation of the menstrual cycle.