Explain how the endocrine system controls the menstrual cycle using FSH, LH and oestrogen.

OCR GCSE Biology A: Gateway Science (J247) — B3.2 Coordination and control — the endocrine system · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

A student learns that the monthly menstrual cycle in women is controlled by hormones released from the pituitary gland and the ovaries.

Model answer (4 marks)

FSH is released by the pituitary gland and stimulates the maturation of an egg in the ovary.
Oestrogen is produced by the ovaries and causes the uterus lining to thicken and develop.
LH is released by the pituitary gland and triggers ovulation, the release of the mature egg.
The hormones travel in the bloodstream to their target organs, where they exert their effects.

Examiner tips

  • Use the exact hormone names (FSH, LH, oestrogen) and their source glands. Show the sequence: pituitary → FSH → follicle growth → oestrogen → endometrium thickening → LH surge → ovulation. Mention transport by blood to target tissues.

Common mistakes

  • Confusing oestrogen with progesterone or vice‑versa. Forgetting to state that FSH and LH are released from the pituitary. Not linking the hormones to their specific actions (e.g., not mentioning endometrium thickening).

Mark scheme (4 marks)

  1. FSH is released by the pituitary gland and stimulates the maturation of an egg in the ovary
  2. Oestrogen is produced by the ovaries and causes the uterus lining to thicken/develop
  3. LH is released by the pituitary gland and stimulates the release of an egg (ovulation)
  4. The hormones are transported in the bloodstream to their target organs

Key terms in this question

FSH · LH · oestrogen · menstrual cycle · endocrine system

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