Transcript Adolescence: Physical Development

Adolescence: Physical Development
Learning Objectives
1.
Describe historical as well as current perspectives on the
period of adolescence.
2.
Discuss the changes that accompany puberty for both girls and
boys, and describe the secular trend.
3.
Discuss the implications of early maturation for girls and boys.
Adolescence: Physical Development
Learning Objectives
4.
Describe sexually transmitted infections, and discuss the
implications of providing students with condoms.
5.
Discuss the leading causes of death in adolescence.
6.
Describe adolescent nutritional needs and weight problems.
Adolescence: Physical Development
Learning Objectives
7.
Explain the most prominent eating disorders as well as gender
differences in their occurrence.
8.
Describe substance use and abuse in adolescence.
Adolescence: Physical Development
Truth or Fiction?

American adolescents are growing taller than their parents.
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Girls are fertile immediately after their first menstrual period.
Adolescence: Physical Development
Truth or Fiction?
 Boys and girls who mature early have higher self-esteem than
those who mature late.
 Most adolescents in the United States are unaware of the risks of
HIV/AIDS.
Adolescence: Physical Development
Truth or Fiction?

Substance abuse is the leading cause of death among male
adolescents in the United States.
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You can never be too rich or too thin.
Adolescence: Physical Development
Truth or Fiction?
 Some college women control their weight by going on cycles of
binge eating followed by self-induced vomiting.
 Substance use and abuse is on the rise among high school
students.
Adolescence: Physical Development
Truth or Fiction?
 Substance abuse is highest among African American and Latino
American high school students.
Puberty
The Biological Explosion
What Is Adolescence?
• Transitional period between childhood and adulthood
• G. Stanley Hall
– Proposed adolescence as separate stage
– Marked by Sturm and Drang
• Sigmund Freud
– Genital stage
• Anna Freud
– Turbulent period
• Current theorists
– Reorganization, not necessarily turbulent or stressful
What Is Adolescence?
• Three Phases of Adolescence
– Early adolescence (11 or 12 – 14 years)
– Middle adolescence (14 – 16 years)
– Late adolescence (16 – 18 or 19 years)
• Tweens
– Earlier age for adolescence
• Emerging Adulthood
– Later age for adolescence
What Is Puberty?
• Puberty is a biological concept
– Attaining sexual maturity and ability to reproduce
• Puberty is controlled by feedback loop
– Hypothalamus – Pituitary gland – Gonads – Hormones
• Sex hormones trigger development of
– Primary sex characteristics
– Secondary sex characteristics
What Happens During the Adolescent Growth Spurt?
• Girls begin their growth spurt earlier than boys
– Reach peak growth in height about 2 years after spurt began
• Continue to grow at a slower rate for another 2 years
– Weight spurt begins about 18 months after height spurt
• Boys catch up to girls and eventually are taller and heavier
• Body shapes differ by sex
– Boys have broader shoulders
– Girls gain almost twice as much fatty tissue
Spurts in Growth
Figure 14.1
Growth Curves for Height and Weight
Figure 14.2
What Happens During the Adolescent Growth Spurt?
• Asynchronous Growth
– Exception to proximodistal growth
• Hands and feet mature before arms and legs
– Reversal of cephalocaudal growth
• Legs reach peak growth before shoulders and chest
• Secular Trend
– May have reached genetic potential
– In industrialized countries
• Middle-upper-class families – stopped growing taller
• Poorer families continue to make gains
– Nutrition and health care are factors
Are We Still Growing Taller Than Our Parents?
Figure 14.3
Pubertal Changes in Boys
• Average age of 11½ – first visible sign of puberty
– Growth of testes accelerates testosterone production
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Body hair growth
Voice deepens – growth of larynx
Acne
Increase in penile erections
– Nocturnal emissions
• Gynecomastia – enlargement of breasts
• About age 20 to 21 – puberty ends
– Epiphyseal closure
Pubertal Changes in Girls
• Increased estrogen production
– Stimulates breast buds
– Promotes fatty tissue in hips and buttocks
• Production of androgen
– Simulates pubic and underarm hair growth
• Estrogen causes labia, vagina, and uterus to develop
• Androgens cause clitoris to develop
Pubertal Changes in Girls
• Menarche
– May begin as early as 9 or as late as 16
– Body weight may trigger menarche
• Hormonal Regulation of Menstrual Cycle
– Ovulate 12 to 18 months after menarche
– Average menstrual cycle is 28 days
• May be irregular during first 2 years
• Psychological Impact of Menarche
– Rite of passage
– Educated and prepared – more positive
The Decline in Age at Menarche
Figure 14.4
What Are the Effects of Early or Late Maturation
on Adolescents
• Boys
– Early maturation – more positive effects
• Popular, more poised, heightened self-worth
– Early maturation – negative effects
• Expectations and demands
– Late maturation
• Not rushed into maturity
• May feel dominated by early-maturing boys
– Lower-income – early maturation is greatest benefit
• Value physical prowess
What Are the Effects of Early or Late Maturation
on Adolescents
• Girls
– Early maturation – more negative effects
• Negative body image
• Feel awkward and conspicuous
• More problems in school and emotional issues
How Do Adolescents Feel About Their Bodies?
• Girls have more negative body image
– Preoccupied with body weight
• By late adolescence body dissatisfaction declines
• Dissatisfaction with body image = feelings of depression
What Brain Developments Take Place
During Adolescence?
• Increase in gray matter
– Gains in thickness of cerebral cortex based on learning – sensory
and motor activities
• Synaptic pruning
– “Use it or lose it”
• Genes and environment play role in shaping the brain
What Happens to the Brain When an Adolescent
Practices Piano Several Hours a Day?
Figure 14.5
Emerging Sexuality and Risks of
Sexually Transmitted Infections
What Kinds of Sexually Transmitted Infections Are There?
• Bacterial infections
– Chlamydia
• Most common STI in adolescents
• Major cause of pelvic inflammatory disease
– Gonorrhea and syphilis
• Viral infections
– HIV/AIDS, genital herpes
– Genital warts caused by HPV
• Linked to cervical cancer
• Vaccine
HIV/AIDS
• Left untreated – lethal
• Risk factors for HIV/AIDS
– Young gay males
– Homeless and runaway youths
– Injecting drugs
• Women and HIV/AIDS
– Minority of cases in US
– Europe, Africa, SE Asia – sexually active teenage girls have higher
rates than older women or young men
Rates per 100,000 Population of AIDS Diagnoses
Among Adolescents Aged 15-19 Years, by Sex
Figure 14.6
What Factors Place Adolescents
at Risk for Contracting STIs?
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Sexual activity
Sex with multiple partners
Failure to use condoms
Drug abuse
What Can Be Done to Prevent STIs?
• Education Strategies
– Increased knowledge about STIs
• Prevention Strategies
– Enhance teens’ sense of control
• Effective decision making and social skills
A Closer Look – Real Life
Preventing HIV/AIDS and Other
STIs: It’s More Than Safe(r) Sex
Health in Adolescence
How Healthy Are American Adolescents?
• Most American adolescents are healthy
• May be less healthy than their parents at the same age
– Lifestyle factors and risky behaviors
What Are the Causes of Death Among Adolescents?
• Death rates for males is twice as great as females
– Males more likely to take risks that end in accidents, suicide, or
homicide
• Accidents
– 60% of teen deaths
– Most involve motor vehicles
– Alcohol is frequently implicated in accidental deaths
• Homicide
– More frequent for poor and in urban areas
– Greatest among African American adolescents
How Much Sleep do Adolescents Need?
• Need 8.5 to 9.25 hours of sleep per night
• Sleep deprivation
– 6 or fewer hours per night
• Reasons for insufficient sleep
– Hectic schedules and commitments
– Brain developments – phase delay
What Are the Nutritional Needs of Adolescents?
• Rapid growth
– Average girl – 1,800 to 2,400 calories
– Average boy – 2,200 to 3,200 calories
• Need for calcium – bone growth
– Females need to build up bone density and prevent osteoporosis
• Nutritional deficits
– Irregular eating habits
– Fast food or junk food
What Are Eating Disorders?
• Gross disturbances in eating patterns
• Anorexia Nervosa
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Weigh less than 85% of desirable body weight
More frequent in females than males
Severe weight loss impacts general health
4 to 5% mortality rate
What Are Eating Disorders?
• Bulimia Nervosa
– Characterized by recurrent cycles of binge eating and purging
– Tend to be perfectionistic about body
What Are the Origins of Eating Disorders?
• Psychoanalytic perspective
– Anorexia is an effort to regress to prepubescence
• Family control issues
• Child abuse, sexual abuse are risk factors
• Societal slender social ideal
– Demands of athletics and activities
• Genetic
Treatment and Prevention of Eating Disorders
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May require hospitalization and nasogastric (tube) feeding
Antidepressants
Family therapy
Cognitive-behavioral therapy
What Is Substance Abuse?
What Is Substance Dependence?
• Substance abuse
– Ongoing use of a substance despite the problems it causes
• Substance dependence
– No control over substance
– Tolerance – body becomes habituated to substance
– Abstinence syndrome – withdrawal symptoms
What Are the Effects of Depressants?
• Slows the activity of the nervous system
• Alcohol
– Lowers inhibitions
– Intoxicant
– Long-term drinking may produce serious physical disorders
• Heroin
– Provides an euphoric “rush”
• Barbiturates
– Legitimate medical uses
– Used illegally to produce a mild euphoria
What Are the Effects of Stimulants?
• Speed up heart beat and other bodily functions
• Nicotine
– Raises rate of burning calories, lowers appetite
– Addictive stimulant in tobacco
• Cocaine
– Euphoria, boosts self-confidence, reduces appetite
• Amphetamines
– Used to stay awake or reduce appetite
– High doses cause restlessness, insomnia, irritability
What Are the Effects of Hallucinogenics?
• Bring on perceptual distortions or hallucinations
• Marijuana
– Used to relax and elevate mood
– Impairs perceptual-motor coordination
– Interferes with short-term memory and learning
• Ecstasy (MDMA)
– Feelings of elation and self-confidence
– Lowers inhibitions and increases risky behaviors
• LSD
– Impairs coordination and judgment
– Hallucinations and paranoid delusions
How Widespread Is Substance Abuse?
• Illicit drug use by 8th- to 12th-grade students has declined
• Incidence of alcohol, cigarettes, and marijuana is relatively high
– Occasional death from alcohol overdose
– Connected with reckless behaviors
• Less than 2% high school students use steroids
– Used to build muscle mass
• More adolescents disapprove of regular drug use than
experimental drug use
What Factors Are Associated with
Substance Abuse and Dependence?
• Experimental use
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Peer pressure, acceptance by peers
Rebelling against moral or social constraints
Curiosity
Escape from boredom
• Imitating parents or adults
• Social Cognitive Theory
– Someone has recommended them or they have observed someone
using them
– Continued use depends on reinforcement
A Closer Look - Diversity
Sex, College Plans, Ethnicity, and
Substance Abuse
What Factors Are Associated with
Substance Abuse and Dependence?
• Predictors of drug use and abuse
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Association with peers who use or tolerate drugs
Parental communication discourages drug use
School problems
Biological factors
How Can We Treat and Prevent Substance Abuse?
• Difficult to treat
– Often doesn’t want to stop
– Relapse problems
– Need to address other disorders and family dysfunctions