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Hormones in human reproduction

Homeostasis and response · Hormonal coordination in humans · note 4 of 7

Spec 4.5.3.4Download these notes (PDF)12 pages

Hormones in human reproductionSpec 4.5.3.4

During puberty, reproductive hormones cause secondary sex characteristics to develop.

HormoneMade byRole
OestrogenThe ovaryThe main female reproductive hormone
TestosteroneThe testesThe main male reproductive hormone. It stimulates sperm production

At puberty eggs begin to mature in the ovaries, and one is released approximately every 28 days. This is called ovulation.

Hormones in the menstrual cycle

HormoneRole in the menstrual cycle
Follicle stimulating hormone (FSH)Causes maturation of an egg in the ovary
Luteinising hormone (LH)Stimulates the release of the egg
Oestrogen and progesteroneInvolved in maintaining the uterus lining
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How the hormones interact

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  • FSH is released by the pituitary gland. It causes an egg to mature in the ovary. It also stimulates the ovary to release oestrogen.
  • Oestrogen causes the lining of the uterus to grow and repair. It inhibits the release of FSH. When oestrogen reaches a high level it stimulates the pituitary gland to release a surge of LH.
  • LH stimulates the release of the egg (ovulation), around the middle of the cycle.
  • Progesterone maintains the lining of the uterus. It inhibits the release of FSH and LH.
  • If progesterone falls, the uterus lining breaks down and the next cycle starts.
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Graph of hormone levels over a 28-day menstrual cycle: FSH highest in the first half, oestrogen rising to a peak just before ovulation, an LH surge at about day 14, and progesterone rising to a peak around day 21 then falling; below, the uterus lining breaks down, grows and is then maintained.Tap to enlarge
Hormone levels across a 28-day cycle. The LH surge triggers ovulation at about day 14; when progesterone falls, the lining breaks down.
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Reading a hormone graph

A graph shows LH peaking sharply at day 14, and progesterone rising to its highest level at day 21 and falling by day 28. State what happens at day 14 and explain what the fall in progesterone at day 28 causes.

  1. The LH peak at day 14 matches ovulation: LH stimulates the release of the egg.
  2. Progesterone helps to maintain the uterus lining.
  3. When progesterone falls, the lining can no longer be maintained.

Answer: An egg is released at day 14. The fall in progesterone at day 28 causes the uterus lining to break down.

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