During the ovulatory phase, which hormone stimulates the follicle to rupture and release the ovum?

• A. Estrogen
• B. Progesterone
• C. Luteinizing
• D. Testosterone

Answer: (C)

During the ovulatory phase of the menstrual cycle, the hormone that plays a pivotal role in stimulating the follicle to rupture and release the ovum is luteinizing hormone (LH). LH is secreted by the anterior pituitary gland and its surge is what triggers ovulation, typically occurring mid-cycle.

As the ovarian follicle matures in the follicular phase, it produces increasing amounts of estrogen. This rise in estrogen levels eventually leads to a surge in LH, which then causes the mature follicle to emerge and release the ovum. The role of LH is crucial as it also helps in the conversion of the ruptured follicle into the corpus luteum, which is instrumental in maintaining the pregnancy should fertilization occur.

Other hormones mentioned, such as estrogen and progesterone, play significant roles in the menstrual cycle but do not directly trigger ovulation. Estrogen primarily regulates the growth of the follicles and prepares the endometrium for potential pregnancy, while progesterone is significant in the luteal phase after ovulation has occurred, supporting the endometrium. Testosterone, while present in females, is not involved in the ovulation process. Understanding the specific actions of these hormones is essential for grasping the dynamics of the ovulatory phase.