Physical Development in Adolescence PDF

Physical Development in Adolescence  Phases of Adolescence Early 11–12 to 14 Rapid pubertal change years Middle 14 to 16 Pubertal changes nearly years complete Late 16 to 18 Full adult appearance, years assumption of ad...

Physical Development in Adolescence  Phases of Adolescence Early 11–12 to 14 Rapid pubertal change years Middle 14 to 16 Pubertal changes nearly years complete Late 16 to 18 Full adult appearance, years assumption of adult roles  Puberty A brain-neuroedocrine process occurring primarily in early adolescence that produces physical changes in height, weight, and sexual maturation. Signals the onset of adolescence Puberty ends before adolescence Growth Spurt Girls: Begins around age 9 peaks at about 11½ Grow about 3½ inches per year Boys: Begins around age 11 peaks at about 13½ Grow about 4 inches per year During adolescence young people: grow about 10 - 11 inches gain about 50 to 75 pounds  Hormonal Changes in Puberty Release of growth hormone (GH) and thyroxine Adrenarche: release of adrenal androgens Estrogens – contribute to girls’ height spurt, development of female sex characteristics, regulation of menstrual cycle. – combine with androgens to stimulate gains in bone density. Testosterone – is released by boys’ maturing testes. – leads to muscle growth, body and facial hair, other male sex characteristics; also contribute to gains in body size. Hormonal Influences on the Body at Puberty  Sexual Maturation Primary sexual characteristics: – Maturation of reproductive organs – Girls: menarche – Boys: spermarche Secondary sexual characteristics: – Girls: breasts – Boys: facial hair, voice change – Both sexes: underarm, pubic hair – Other visible parts of the body that signal sexual maturity Timing and Sequence of Body Changes in Puberty  Secondary Sex Characteristics in Boys Broadening of chest and shoulders Deepening of voice and appearance of facial hair Increase in size of genitals Appearance of body hair and pubic hair  Secondary Sex Characteristics in Girls Widening of hips and appearance of Appearance of hair in the armpit pubic hair Development of breasts  Individual Differences in Pubertal Growth Timing of pubertal changes is influenced by heredity nutrition and exercise geographical location SES and ethnic group early family experiences stressors Timing of Menarche  Reactions to Pubertal Changes Pubertal events affect self-image, mood, interaction with parents and peers. Girls’ responses to menarche depend on – prior knowledge and family support. – cultural attitudes toward puberty and sexuality. Tribal and village societies may celebrate puberty with initiation ceremony. Western adolescents – have no widely accepted marker of maturity. – gain partial adult status at many different ages.  Emotional and Social Responses to Puberty Adolescent moodiness – is modestly linked to higher hormone levels. – is linked to negative life events. Moods are less stable in younger than older adolescents. Parent–child relationships: – Puberty is linked to rise in intensity of parent–child conflict. – Psychological distancing may be modern substitute for departure of the young from the family group. Both generations benefit from warm family bonds throughout lifespan.  Consequences of Pubertal Timing Boys Girls Early- Popular Unpopular, withdrawn maturing Confident, independent Low confidence, Positive body image negative body image More involved in risky behaviors Early sexual intercourse Late- Unpopular Popular maturing Transient emotional Sociable, lively difficulties until they Positive body image catch up physically with Better academic peers performance  Early Maturation – Girls The effects of early maturation are especially negative for girls Early maturing girls are at risk for a variety of problems: Depressed mood Negative body image Eating disorders Substance use Delinquency School problems Conflicts with parents  Late Maturation – Girls Late maturing girls have few of the problems that early- maturing girls have Although they can suffer from: Teasing Negative body image (during the years when other girls have begun to develop) However, by their late teens they tend to have a more favorable body image than other girls They are more likely to end up with the lean body build that tends to be regarded as attractive in Western majority cultures  Early Maturation – Boys The effects of early maturation tend to be positive for boys Early maturing boys have: More favorable body image Higher popularity Not everything is favorable; they tend to be involved in: Substance use Delinquency Sex  Late Maturation – Boys Late maturing boys show evidence of problems Compared with boys who mature “on time,” late maturing boys have higher rates of: Alcohol/substance use Delinquency Lower grades in school Deviant behavior  Brain Development in Adolescence White matter increases, gray matter declines: – Pruning of unused synapses continues. – Myelination accelerates, strengthening connections among brain regions. – Prefrontal cortex becomes more effective “executive.” Neurons become more sensitive to excitatory neurotransmitters. Changes in emotional/social network outpace development of prefrontal cognitive-control network.  Sleep and the Adolescent Brain During puberty: – Circadian rhythm (internal biological clock) is reset. – Melatonin (sleep hormone) is released later. As a result, adolescents fall asleep about 2-3 hours later and wake up 2-3 hours later Adolescent Sleep-Wake Cycle  Sleep and the Adolescent Brain Adolescents need almost as much sleep as they did in middle childhood: about 9 hours Most adolescents get far less sleep than they need: 7-8 hours  Sleep Habits in Adolescence Teenagers go to bed later due to – biological changes. – evening social activities, use of screen media. Sleep deprivation – affects performance on cognitive tasks. – may lead to anxiety and depressed mood. – is associated with high-risk behaviors.