Question

Describe the roles of pituitary and ovarian hormones during the menstrual cycle in a human female. [5]

Answer 1

Role of Hormones in Menstrual Cycle:

1. The chemical messengers in our body called hormones, released by various endocrine glands are responsible for many changes in a human body.
2. Menstruation is a slave to certain hormones.
3. Every phase of the menstrual cycle is influenced by a female hormones namely estrogen, progesterone, FSH and LH.
4. The variation in the level of each of these hormones decides the phase which a girl undergoes.
5. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are secreted by the anterior pituitary.
6. FSH stimulates the growth of ovarian follicles that secrete estrogen.
7. Progesterone is secreted by the corpus luteum.
8. The secretion of FSH and LH gradually increases during the follicular phase.
9. They stimulate the development of follicles and the release of estrogen from them.
10. Estrogen stimulates the proliferation of the endometrium.
11. The level of LH and FSH peaks in the middle of the cycle.
12. LH induces ovulation.
13. There is a sudden surge in LH level just before ovulation.
14. After ovulation, the ruptured follicle develops into the corpus luteum, which secretes progesterone, hence the level of progesterone increases in the luteal phase.
15. Progesterone is required for the maintenance of the endometrium for implantation.
16. In the absence of fertilisation, corpus luteum regresses and progesterone level decreases.
17. It leads to the disintegration of the endometrium and menstrual flow occurs.

Diagram:

Diagram: Role of hormones in menstrual cycle.