16.5) Sex hormones in humans
Puberty is the stage in life when a child’s body develops into an adult’s body. The changes take place gradually, usually between the ages of 10 and 16.
Changes occur at puberty because of hormones:
- testosterone – produced by the testes – controls the development of male secondary sexual characteristics
- oestrogen – produced by the ovaries – controls the development of female secondary sexual characteristics
The menstrual cycle:
- The ovaries release an ovum about every 4 weeks.
- In preparation for this the lining of the uterus wall thickens, so that an embryo can embed itself if the release ovum is fertilised.
- If no implantation occurs, the uterus lining breaks down. The cells, along with blood are passed out of the vagina. This is called a menstrual period.
- Several hormones control this cycle: