2 1. Introduction 2. Fact or Fiction? 3. Puberty Begins 4. The Transformations of Puberty 5. Possible Problems 6. Closing Thoughts

Introduction 3 [Video: Physical Development Introduction]

Fact or Fiction?FictionFact 1. Although the sequence of puberty is variable, the age of onset is not. 2.The level of stress in a child’s family can influence the onset of puberty. 3. Girls and boys who mature earlier or later than their friends have a difficult time adjusting to puberty. 4. By the end of adolescence, cognitive ability is equal to that of a fully mature adult. Physical Development 4

Hypothalamus Hormones Pituitary Adrenal glands Gonads (ovaries or testicles) Increase in many hormones, including testosterone and estrogen Growth spurt Primary sex characteristics Secondary sex characteristics Growth hormone (GH) Gonadotropin - releasing hormone HPA axis and HPG axis What is the biological sequence of puberty? hormone: An organic chemical substance; produced by one body tissue and conveyed via the bloodstream to another to affect some physiological function. Hormones 5

Genes and GenderBody Fat 2/3 of variation in age of puberty is genetic, evident in families and ethnic groups Most girls reach at least 100 pounds (45 kilograms) before they can experience their first period What is the relationship between age and puberty? (Ge et al., 2007; Susman et al., 2010; van den Berg & Boomsma, 2007) (Berkey et al., 2000) Stress Although the link between stress and puberty is known, not every scientist agrees that stress causes early puberty (Ellis, 2004) Age and Puberty secular trend: long-term upward or downward direction of a certain set of statistical measurements. 6 When Will Puberty Start?

What are some effects of early- or late-arriving puberty? Early-maturing girls Tend to have lower self-esteem, more depression, and poorer body image than do other girls (Compian et al., 2009). Less exercise contributes to their difficulties (Davison et al., 2007). Those with older boyfriends are at increased risk for using drugs and alcohol (Wiechold et al., 2003). May face relational bullying and physical violence (Shreck et al., 2007). Early- and late-maturing boys Today, early maturing boys are more aggressive, law-breaking, and alcohol abusing than later-maturing boys (Biehl et al., 2007; Lynne et al, 2007). According to research from Finland, slow-developing boys tend to be more anxious, depressed, and afraid of sex (Lindfors et al., 2007). Too Early, Too Late 7

When Will Puberty Start? 8 [Video: Timing of Puberty: Girls]

When Will Puberty Start? 9 [Video: Timing of Puberty: Boys]

What are symptoms of the eating disorders anorexia and bulimia nervosa? AnorexiaBulimia Refusal to maintain a weight that is at least 85 percent of BMI. Intense fear of weight gain. Disturbed body perception and denial of the problem. Absence of menstruation (in adolescent and adult females). Bingeing and purging at least once a week for three months. Uncontrollable urges to overeat. A distorted perception of body size. Eating Habits and Body Image 10

Nutrition 11 [Video: Eating Disorders: Experience Eating Disorders]

Nutrition 12 [Video: Eating Disorders: Coping with Eating Disorders]

Growing Bigger and Stronger What are some differences in growth between boys and girls? Throwing Performance of Boys and Girls, Age 6 to 18 Ball throw for distance Meters Age (years) Source: Malina et al., 2004, p Running Speed of Girls and Boys, Age 6 to yard (27.4-m) dash Running time (seconds) 3 Age (years) Source: Malina et al., 2004, p Boys Girls 13

Sexual Maturation By percent, how many adolescents are sexually active and use condoms? Sources: Nic Gabhainn et al., 2009; MMWR, June 4, 2010 Country France Israel Canada United States England Russia Sexually Active (% of total) Used Condom at Last Intercourse (% of those sexually active) Condom Use Among 15-Year-Olds (Tenth Grade) 14

Brain Development Are teenage brains like those of children or adults? 520 Age Gray Matter The scale represents the proportion of gray matter A B C D E F G H I J K N Q M L O P G C B A H J I K

Brain Development 16 [Video: Brain Growth, Infancy Until Age 18]

What are some hazards that teenage mothers face? Fact or Fiction?FictionFact 1. What does early sex correlate with? 2. Compared with 100 years ago, how many teenage mothers are unwed? 3. What is the expense of raising a child today? 4. What about receiving help from the mothers of teenage mothers? 5. What other complication can teenage mothers face? Depression and drug use. 85 percent today, compared with 100 years ago when most teenage mothers were wed. Raising a child is more complex and expensive than in the past. Mothers of teenagers are usually employed and less available to help with their young daughters and new grandchildren. These days, sexually transmitted infections are more common and dangerous. Sex Too Soon 17

Sex Too Soon 18 [Video: A Young Mother in Brazil]

Sex Too Soon 19 [Video: A Young Mother in Nepal]

Sex Too Soon 20 [Video: A Young Mother in Uganda]

Drug Use by U.S. High School Seniors in the Past 30 Days Source: Johnston et al., Drug Use and Abuse How many and what kind of drugs do high school students use? Percent reporting use of drug Year ‘78‘80‘82‘84‘86‘88‘90‘92‘94‘962000‘98‘02‘04‘06‘08 AlcoholCigarettes Other illicit drugs (not marijuana) Marijuana CocaineAmphetamines 21

Learning from Experience What are some learning benefits that occur due to physical growth during adolescence? Benefits of Adolescence More active reward center in brain and production of positive neurotransmitters Reactions become lightning fast with increased myelination and slower inhibition Synaptic brain growth occurs before another wave of pruning Prefrontal cortex of brain still developing 22

How does the behavior of adolescents change as a result of some of the physical changes they experience during this phase of life? Closing Thoughts 23