Experiencing The Lifespan JANET BELSKY Experiencing The Lifespan 3rd edition Chapter 8: Physical Development Copyright © 2013, 2011 by Worth Publishers

Figure 8.1 The secular trend in puberty: Notice that the average age of menarche dramatically declined in developed countries during the first half of the twentieth century. Is this decline continuing? Stay tuned for surprising answers later in this chapter. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 8.2 The HPG axis: The three-phase hormonal sequence that triggers puberty: As you can see here, in response to various genetic and environmental influences, the hypothalamus releases a hormone that stimulates the pituitary gland to produce its own hormones, which cause the ovaries in girls and the testes in boys to grow and secrete estrogens and testosterone, producing the physical changes of puberty. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 8.3 Changes in blood hemoglobin and red blood cells during puberty in males and females: At puberty, increases in the amount of hemoglobin in the blood and in the number of red blood cells cause children of both sexes to get far stronger. But notice that these changes are more pronounced in boys than in girls. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 8.4 The sequence of some major events of puberty: This chart shows the ages at which some important changes of puberty occur in the average boy and girl. The numbers below each change show the range of ages at which that event begins. Notice that girls are on a slightly earlier timetable than boys, that boys’ height spurt occurs at a later point in their development, and that there are dramatic differences from child to child in the timing of puberty. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Table 8.1 Predicting a Girl’s Chances of Early Puberty: Some Questions JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 8.5 Getting your first bra: To measure how girls undergoing puberty feel around their parents—without asking them directly—researchers used this specially constructed card and asked children of different ages to describe what was happening and asked “How do the mother, the father, and the girl feel?” JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 8.6 The desire to be “smaller” among average and underweight Irish girls, aged 12 to 19: Notice that with 3 out of 4 “average weight” girls wanting to be thinner and a significant proportion of underweight girls still wanting to shed pounds, female teens in Ireland are clearly buying into the destructive messages of the thin ideal. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Table 8. 2 Is a Teenager at Risk for Serious Body Dissatisfaction Table 8.2 Is a Teenager at Risk for Serious Body Dissatisfaction? A Checklist JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 8.7 Encouraging snapshots of twenty-first century teenage sexuality in the United States: This news about teenage sex is good! Fewer young people are having intercourse and more sexually active adolescents report using contraception. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Table 8.3 Designing a Teenager-Friendly Sex Education Program: A Summary Table JANET BELSKY Copyright © 2013, 2011 by Worth Publishers