Question

1. Explain the role of FSH and LH in the reproductive systems of humans. What does each hormone do, and what parts of the reproductive tract are affected?

2. Why is the action potential considered an "all or nothing" event?

3. Describe two ways in which the nervous and endocrine systems interact to help regulate

Answer 1

1. In both male and female reproductive system, the cycles are controlled by the hormonal interaction from the hypothalamus and anterior pituitary. When this reproductive hormone is required, the hypothalamus sends a gonadotropin-releasing hormone (GnRH) to the anterior pituitary causing the release of follicle stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary into the blood.

In the male reproductive system - during the onset of puberty, the hypothalamus for the first time causes the release of FSH and LH. FSH enters the testes and stimulates the Sertoli cells which begin to facilitates spermatogenesis. LH also enters the testes and stimulates the interstitial cells of Leydig which makes and releases testosterone into the testes and the blood. Testosterone is the hormone which is responsible for the secondary sexual characteristics in the male.

In the female reproductive system - The anterior pituitary hormone causes the release of the hormones FSH and LH. FSH stimulates the development of egg cells, called ova, which further develops into follicles.LH also stimulates the development of ova (egg cell), induction of ovulation, and also stimulates the production of estradiol and progesterone by the ovaries. The first half phase of the ovarian cycle is the follicular phase, where slowly rising levels of FSH and LH causes the follicle to grow on the surface of the ovary. This process prepares the egg for ovulation. In ovulation, FSH and LH stimulate the maturation of one of the growing follicles. The second phase is the luteal phase, where LH stimulates the growth of corpus luteum from the follicular tissue.