At the beginning of puberty the pituitary gland, again in response to chemical messages from the hypothalamus, also begins to produce the hormones called gonado-trophins, which stimulate the gonads to produce sex hormones. Girls’ ovaries produce the hormones oestrogen and progesterone, and boys’ testes produce testosterone. These sex hormones circulate in the blood and affect the growth and development of many parts of the body, resulting in the striking differences between children and adults known as the secondary sexual characteristics. The most obvious changes are seen in the breasts, genitals, pubic and underarm hair, voice change and, in boys, beard growth.
At the same time as the secondary sexual characteristics are developing, hormones are also influencing the internal reproductive organs towards reproductive maturity. In girls the most clear-cut event of puberty, the first menstruation (the menarche), happens between 18 months and three years after the beginning of the growth spurt. A comparable event in boys is the first ejaculation. This often happens during sleep and may not be announced, so it’s more difficult to date and has less social importance than the beginning of menstruation.
You’ll notice other changes at puberty. You’ll develop an enormous appetite to give you enough nourishment to cop with the growth spurt. As pubic and underarm hair grows, some specialised sweat glands develop in these regions. You sweat more, and your sweat smells different! Your scalp hair may become coarser, darker and curlier, and you may develop dandruff. Your nose takes on its adult shape. The effect of hormones on skin often results in some degree of acne.
Though this is a women’s health book, in this introduction I’ve included some information about what happens to boys at puberty. Girls may like to know what happens to their brothers and friends.
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