Study the following flow chart. Name the hormones involved at each stage. Explain their functions.

Explanation

(a) Hypothalamus secretes GnRH (gonadotropin releasing hormone). GnRH acts on pituitary gland and induces it to secrete gonadotropins LH, FSH.
(b) LH and FSH. LH or luteinising hormone also called interstitial stimulating hormone (ICSH) acts on Leydig cells of POTA testes to produce testosterone and other androgens.
`(c_(1))` Testosterone acts on spermatogonia for initiating spermatogenesis. FSH acts on sertoli cells to provide attachment, nourishment and stimulate spermatids to undergo spermiogenesis.
`(c_(2))` Follicle stimulating hormone stimulates an ovarian follicle to grow and reach maturity forming Graafian follicle. The latter secretes estrogen. LH or Luteinising hormone brings out ovulation and converts the empty follicle into corpus luteum.
Corpus luteum secretes hormone progesterone. Progesterone acts on uterine endometerium. It helps in maintaining pregnancy.