Question

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

Answer 1

1. Pyramid of energy is a graphical representation of the amount of accumulated energy per unit area in different trophic levels of a food chain.
2. An energy pyramid is always upright because there is a gradual decrease in energy at successive trophic levels. This happens because, according to the 10% law of energy transfer, only 10% of the total energy is transferred from one trophic level to another.
3. The energy is highest at the producer level and it gradually decreases on moving from herbivores to carnivores.
4. As the oestrogen levels increase the endometrium begins to regenerate along with the development of uterine glands and network of blood vessels.
5. The corpus luteum starts secreting progesterone, oestrogen, and inhibin. The endometrium proliferates under the influence of these hormones, as do the endometrial gland and blood vessels. Inhibin inhibits FSH and GnRH secretion.
6. When there is no fertilisation, the corpus luteum degenerates, progesterone levels drop, and the next menstrual cycle begins.
7. Thus, pituitary and ovarian hormones work together to regulate all phases of the menstrual cycle.