Granulosa cells are specialized cells found in the ovaries, specifically within the ovarian follicles. They play a crucial role in the development of oocytes (egg cells) by providing support and nourishment. These cells are responsible for producing hormones, such as estrogen, which are essential for regulating the menstrual cycle and supporting reproductive health. During the maturation of follicles, granulosa cells undergo changes and proliferate. They also form a protective layer around the oocyte, helping to facilitate communication between the oocyte and the surrounding environment. This interaction is vital for the proper growth and development of the oocyte and the overall function of the ovaries.