Final answer:
FSH stimulates the growth and maturation of ovarian follicles primarily during the follicular phase of the menstrual cycle and plays a role in the ovulation phase as well, contributing to the release of a mature egg.
Step-by-step explanation:
The hormone FSH, or follicle-stimulating hormone, stimulates the growth and maturation of ovarian follicles during a woman's menstrual cycle. Specifically, in the follicular phase of the menstrual cycle, FSH is secreted by the anterior pituitary gland after the stimulation of the hypothalamus by GnRH (gonadotropin-releasing hormone). The anterior pituitary gland releases FSH, which then travels to the ovaries and binds to receptors on the granulosa and theca cells of the follicles, causing them to grow. This leads to the expansion of five or six tertiary follicles.
Following the follicular phase, ovulation is characterized by the maturation of the dominant follicle, which is also stimulated by FSH as well as luteinizing hormone (LH). The role of FSH is crucial for female reproductive health as it ensures the proper development of follicles, which are necessary for the release of a mature egg during ovulation.