Menstruation
Biology: Cambridge International GCSE Supplement, topic 16.5.2
The Menstrual Cycle
The menstrual cycle is a monthly cycle, which involves the maturation and release of an egg. If sexual intercourse has occurred, this can result in pregnancy.
Key hormones
- The menstrual cycle is controlled by four hormones from the endocrine system:
- Follicle Stimulating Hormone (FSH)
- Oestrogen
- Luteinising Hormone (LH)
- Progesterone
Stages
- The menstrual cycle can be divided into four stages depending on the levels of the hormones.
Eggs
- A female is born with all of her eggs ready, but only one egg will mature each month once the female reaches puberty.
Test yourself on Menstruation
How frequent is the menstrual cycle?
What happens on day one of the next menstrual cycle?
In females, puberty triggers the menstrual cycle. Which of the following are true of the menstrual cycle?