Hormonal Control of the Menstrual Cycle — AQA GCSE Biology
The menstrual cycle is controlled by four hormones that interact over about 28 days.
Puberty and sex hormones
At puberty, sex hormones cause secondary sexual characteristics to develop:
- Testosterone (from the testes) stimulates sperm production.
- Oestrogen (from the ovaries) is the main female hormone.
The four hormones of the menstrual cycle
| Hormone | Where from | Role |
|---|---|---|
| FSH (follicle-stimulating hormone) | pituitary | causes an egg to mature in the ovary |
| Oestrogen | ovaries | causes the uterus lining to build up; stops FSH; triggers LH |
| LH (luteinising hormone) | pituitary | triggers the release of the egg (ovulation) at about day 14 |
| Progesterone | ovaries | maintains the uterus lining; falling levels cause the lining to break down (menstruation) |
How the hormones interact (Higher Tier)
- FSH stimulates the egg and causes oestrogen release.
- Rising oestrogen inhibits FSH and stimulates LH.
- LH triggers ovulation.
- Progesterone maintains the lining and inhibits FSH and LH.
- If progesterone falls (no pregnancy), the lining breaks down.
Exam tips
- Learn the four hormones, where each is made, and its role.
- FSH matures the egg; LH triggers ovulation (~day 14).
- Oestrogen builds the lining; progesterone maintains it.
- For Higher Tier, explain how the hormones interact to control the cycle.