Hormones in reproduction
Home learning focus
The testes produce testosterone, the ovaries produce oestrogen. Learn about hormones in reproduction.
This lesson includes:
- two videos to help you understand about hormones in reproduction
- two practise activities to help reinforce learning
Watch this video about sex hormones.
Sex hormones and puberty
The testes produce testosterone, the male sex hormone which is responsible for puberty in boys.
The ovaries produce oestrogen, a female sex hormone which is responsible for puberty in girls and the regulation of the menstrual cycle.
These hormones cause secondary sexual characteristics to develop at puberty.
|Voice breaks (gets deeper)||Breasts develop||Underarm hair grows|
|Testes and penis get bigger||Ovaries start to release egg cells (the menstrual cycle starts)||Pubic hair grows|
|Testes start to produce sperm cells||Hips get wider||Body smell gets stronger|
|Shoulders get wider||Emotional changes|
|Hair grows on face and chest||Growth rate increases|
The reproductive system of a child is not mature. It needs to change as a boy or girl develops into an adult, so that the system is fully working. The time when the changes happen is called puberty.
Most girls begin puberty between ages 8 and 14, with an average of 11. Girls develop more quickly than boys and most finish puberty within four years. Most boys begin puberty between ages 9 and 14, with an average of 12. Most boys finish puberty within six years.
The time between puberty and adulthood is called adolescence.
The menstruation cycle and hormones
In this film, Greg Foot describes the interaction of FSH, LS, oestrogen and progesterone in the menstrual cycle. Have a pen and paper handy to make notes.
The menstrual cycle is a recurring process which takes around 28 days. During the process, the lining of the uterus is prepared for pregnancy. If implantation of the fertilised egg into the uterus lining does not happen, the lining is then shed. This is known as menstruation.
Several hormones control this cycle – for example, they are involved in controlling the release of an egg each month from an ovary, and changing the thickness of the uterus lining.
|FSH (follicle stimulating hormone)||Pituitary gland||Causes an egg to mature in an ovary. Stimulates the ovaries to release oestrogen|
|Oestrogen||Ovaries||Stops FSH being produced (so that only one egg matures in a cycle). Repairs, thickens and maintains the uterus lining. Stimulates the pituitary gland to release LH.|
|LH (luteinising hormone)||Pituitary gland||Triggers ovulation (the release of a mature egg)|
|Progesterone||Ovaries||Maintains the lining of the uterus during the middle part of the menstrual cycle and during pregnancy|
If a woman becomes pregnant, the placenta produces progesterone. This maintains the lining of the uterus during pregnancy and means that menstruation does not happen.
Try the activities below to test your knowledge.
There's more to learn
Have a look at these other resources around the BBC and the web.