These changes involve nearly all organs and structures of the body.
The age of puberty varies according to genetic,racial,socioeconomic and nutritional factors.
Usually boys know the onset of puberty at age 9-14 years old and girls arround 8-13 years old.
The principle manifestations of puberty:
1.The adolescent growth spart:
This is an acceleration fallowed by deceleration of growth in most skeletal dimensions terminated by fusion of epiphysis and final adult height.
In girls the most rapid growth is 25 cm,it occurs early before the development of secondary sexual characters.In girls the first sign of puberty is increase in height velocity.
In boys the peak height velocity is 28 cm.It starts on the average 2 years after the average age of onset in girls.
During puberty the growth spurt is controled by hormons. (sex steroids,thyroid hormone).
2.Development of gonads:
In boys the first sign of puberty is the growth of the testes.
3.Development of secondary sexual characters:
In girls appears :
Breast development (controlled by estrogen) .
Breast development stages:
-stage 1:elevation of papilla only
-stage 2 (breast bug stage): elevation of breast and papilla as a small mound elargement of areolar diameters.
-stage 3: further enlargement of breast and areola with no separation of their contours
-stage 4: projection of areola and papilla to form a secondary mound above the level of the breats
-stage 5 (mature stage):projection of papilla only resulting from recession of the areola to the general contour of the breast.
Pubic hair:(contolled by adrenal androgen)
Axillary hair.
Other features: in girls increased size of ovaries and uterus.In boys: the growth of testes and penis,acne,voice change and facial hair that occurs late stage of puberty.
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