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:
|Boys only||Boys and girls||Girls only|
|Voice breaks||Pubic hair grows||Voice deepens gradually|
|Hair grows on face and body||Underarm hair grows||Hips get wider|
|Body becomes more muscular||Sexual organs grow and develop||Breasts develop|
|Testes start to produce sperm cells||Ovaries start to release egg cells - menstruation starts|
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 pregnancy 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 and thickens 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.