A level Biology exam revision resources written by A level Examiners


There are 2 sets of hormones involved

Pituitary Hormones - released from the pituitary gland in the brain (Sometimes called Gonadotrophins)

  • FSH : Follicle Stimulating Hormone
  • LH : Luteinizing Hormone

Ovarian Hormones - released from the ovaries (the examiners to simplify things talk about oestrogen as being released from the follicle and progesterone as being released from the corpus luteum - however in reality there is actually some overlap)

  • Oestrogen; This repairs the uterine lining.
  • Progesterone; This maintains the uterine lining.
  • Both have feedback effect on the secretion of pituitary hormones.
  • FSH is released by the pituitary gland into the bloodstream and it stimulates the growth of a follicle in an ovary.
  • The developing follicle in the ovary produces oestrogen.
  • Rising oestrogen levels inhibits FSH production and promotes LH production.
  • LH stimulates follicle development and its conversion into the corpus luteum.
  • Above a higher threshold level rising oestrogen levels stimulates an increase in FSH, which leads to
  • A surge of FSH (and LH) which brings about ovulation.
  • LH stimulates progesterone production by the corpus luteum.
  • Progesterone inhibits FSH and LH production and prevents more follicles from developing while it is present at a high concentration.
  • The falling levels of LH cause the corpus luteum to degenerate causing progesterone levels to fall and starting the cycle again.

Hormone Effects

  • stimulates the growth & development of the follicle.
  • stimulates secretion of oestrogen.
  • enhances effect of LH in stimulating ovulation.

  • stimulates the final development of the follicle.
  • stimulates ovulation.
  • stimulates the development of the corpus luteum.
  • stimulates production of progesterone.

  • stimulates repair of uterine lining.
  • at high conc. inhibits FSH, however during 'pituitary hormone surge' it stimulates further FSH production.
  • as conc. peaks stimulates release of LH.

  • maintains uterine lining.
  • inhibits release of FSH.
  • inhibits release of LH.
  • fall in conc. results in menstruation.
  • fall in conc. removes inhibition of FSH and allows a new cycle to start.

Figure 1 : The Human Menstrual Cycle
The Human Menstrual Cycle

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