|
Puberty is initiated by hormones. The ovaries begin to produce increased amounts of estrogens.
The most visible signs of puberty are an intensive burst of growth and development of the secondary sex characteristics. But this is also the time when the external and internal sex organs, which are already present in rudimentary form before birth, begin to grow and mature and become fully functional.
Growth and body proportions
In girls the period of most intensive growth is between the ages of 12 and 13. The increasing estrogen production leads to development of the typical female fat distribution with increased fat deposits on the hips and thighs. The mons pubis, which also consists mainly of fat deposits, becomes more prominent.
It is the estrogens that are responsible for closure of the growth plates in the long bones and thus the termination of longitudinal growth at the age of about 16 or 17.
Development of the breasts (telarche)
The first noticeable change at the beginning of puberty is in the breasts. At the age of about 10 to 13 the breasts begin to grow. Of course the timing varies considerably from person to person so the ages given here are only average ages. First breast buds appear. The areola becomes larger. The glandular tissue continues to grow and the breast becomes more rounded. The areola gradually becomes darker as a result of increased pigmentation. By the age of about 16 the breast is usually fully developed. The breast growth may be asymmetric, i.e. one breast may initially be larger than the other. However, by the end of breast development these differences have usually evened out. Nevertheless, small differences in size almost always remain. While the glandular tissue is growing it is sometimes very tender.
Pubic and axillary hair
The increasing production and activity of the sex hormones lead to the growth of pubic hair and underarm hair. In girls it is usually fully developed by the age of 14.
|
