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1、2020/9/24,1,Outline,Puberty: An overview Somatic development The timing and tempo of puberty The psychological and social impact of puberty Eating disorders Physical health and health care in adolescence,2020/9/24,2,Of all the developments that take place during the second decade of life, the only t
2、ruly inevitable one is physical maturation - Steinberg,2020/9/24,3,Puberty is considerably affected by the context in which it occurs Physical development is influenced by a host of environmental factors, and the timing and rate of pubertal growth vary across regions of the world, SES, ethnic groups
3、, and historical eras In contemporary society, the average girl reaches menarche between 12th and 13th birthday,2020/9/24,4,Physical and sexual maturation profoundly affect the way in which adolescents view themselves and the way in which they are viewed and treated by others Social environment exer
4、ts a tremendous impact on the meaning of puberty and on its psychological and social consequences The influence of early or late maturation may differ in regard to the peer group or social context where adolescents live at a given time,2020/9/24,5,1. Puberty: An overview,Puberty : pubertas in Latin,
5、 means “adult”, i.e. refers to the period during which an individual becomes capable of sexual reproduction More broadly speaking, puberty encompasses all the physical changes that occur in the growing girl or boy as she/he passes from childhood into adulthood,2020/9/24,6,1. Puberty: An overview,Chi
6、ef manifestation of puberty (Marshall, 1978) Rapid acceleration in growth: dramatic increases in both height and weight Development o primary sex characteristics,including the further development of the gonads, or sex glands Development of secondary sex characteristics, involving changes in the geni
7、tals and breast, and growth of pubic, facial, and body hair, and the further development of the sex organs,2020/9/24,7,1. Puberty: An overview,Chief manifestation of puberty (Marshall, 1978) Changes in body composition, specifically, in the quantity and distribution of fat and muscle Changes in the
8、circulatory and respiratory systems, which lead to increased strength and tolerance for exercise,2020/9/24,8,The endocrine system（内分泌系统）,Endocrine glands secret hormones Specialized hormones carry messages to particular cells in the body, and the bodys cells designed to receive hormonal messages sel
9、ectively,2020/9/24,9,The endocrine system,Puberty may appear to be rather sudden, judging from its external signs, but, in fact, it is part of a gradual process that begins at conception (Peterson P: pituitary gland(垂体腺), G: gonad(性腺) Hypothalamus controls pituitary gland Pituitary gland controls ho
10、rmone levels in general Gonad release sex hormones - androgens in case of testes and estrogens in case of ovaries Hypothalamus responds to the levels of sex hormones circulating in the body,2020/9/24,12,Figure 1 Levels of hormones are regulated by a feedback systemcomposed of hypothalamus, pituitary
11、 gland, and gonads,促黄体激素释放因子,促卵泡激素释放因子,促黄体激素,促卵泡激素,2020/9/24,13,The endocrine system,During adolescence, the average male produces more androgens than estrogens, and the average female produces more estrogens than androgens (Petersen Collaer Right: gain in height per year for the average male and fe
12、male youngster,2020/9/24,21,Changes in stature and the dimensions of the body,The composition of the skeletal structure also changes Bones become harder, more dense, and more brittle At the end of puberty, the ends of the long bones in body are closed, which terminates growth in the height Much of t
13、he height gain during puberty results from an increase in torso length rather than in leg length,2020/9/24,22,Changes in stature and the dimensions of the body,Young adolescents often appear to be out of proportion physically, because of asynchronicity in growth,2020/9/24,23,Changes in stature and t
14、he dimensions of the body,The spurt in height during adolescence is accompanied by an increase in weight, which result from an increase in both muscle and fat There are sex differences in the increase of muscle and fat, specifically, muscular development is rapider for boys than for girls, and sex d
15、ifference is reversed in the case of fat increase (see figure 3 in next page for the sex differences in muscular and fat development ),2020/9/24,24,Figure 3 Muscle and body fat for individuals of average height at each age,2020/9/24,25,Changes in stature and the dimensions of the body,The result of
16、these sex differences in growth is that boys finish adolescence with a muscle-to-fat ratio of about 3:1, and girls 5:4 Implication for understanding why sex differences in strength and athletic ability often appear for the first time during adolescence About half of the sex differences in physical performance during early adolescence results simply from the difference in body fat (Smoll Surbey, 1990),2020/9/24,45,3. The timing and tempo of puberty,Group difference
