Adolescence: Biosocial Development – Ch. 14 Adolescent/Adult Development Feb 1-8, 2010 Classes #6-9

Puberty Begins…  Period of rapid physical growth and sexual maturation typically completed three to four years after first visible signs  Person attains adult size, shape, and sexual potential

Visible Changes: Girls  Onset of breast growth  Initial pubic hair  Growth spurt  Widening of hips  First menstrual period  Completion of pubic hair growth  Final breast development

Visible Changes: Boys  Growth of testes  Initial pubic hair  Growth of penis  First ejaculation  Growth spurt  Voice deepening  Beard  Completion of pubic hair growth

 Puberty begins with hormone production in brain hormones from hypothalamus trigger production in pituitary glands in turn this triggers hormone production in adrenal glands and sex glands (gonads)  To regulate body functions and changes, many hormones follow this route, the HPA(hypothalamus/pituitary/adrenal) axis Hormones

Direct Effects on Emotions  Rapidly increasing hormone levels precede rapid arousal of emotions  Hormonal levels correlate with quick shifts in emotional extremes

Direct Effects on Emotions: Girls  Hormonal changes during menstrual cycle produce mood changes

Direct Effects on Emotions: Boys  This increase in hormones precipitates thoughts about sex and masturbation

Indirect Effects on Emotions  Hormone levels produce visible signs of sexual maturation, which in turn create expectations of new maturity Social responses to biological signs trigger adolescent moods and reactions  One’s culture affects thoughts of sex First sexual intercourse occurs at different ages in different cultures

Indirect Effects on Emotions  Schwab et al. (2001) Participants:  56 “delayed-puberty” adolescents Method:  24 month treatment Alternating prescription of estrogen or placebo given to girls Alternating prescription of testosterone or placebo given to boys

Schwab et al. (2001)  Results: Significant positive hormone effects: were found:  For girls: Perceptions of increased romantic appeal and closer friendships  For boys: Perception in athletic ability increased  For both sexes: Perceived job competence increased

Cultural differences…  Sexual intercourse: US and Netherlands:  For both sexes: 25% by 14 50% by 17 90% by 21 Finland and Norway: Girls earlier Greece and Portugal Both sexes later

Sex, Genes, and Weight  Girls on average are about two years ahead of boys  Menarche easier to date than Spermarche  Timing can be affected by genetics, ethnicity, and body fat Individuals with stockier builds experience puberty earlier Chronic malnutrition limits fat, thus delaying puberty by several years

Stress in Families  Family conflict may cause earlier onset of puberty or irregular periods stress levels affect hormone production stress probably affects hormones causing puberty  Stress hypothesis gained support when researchers identified two factors influencing early puberty conflicted relationships with family unrelated man living in the home

Too Early or Too Late  Early-maturing girl may be teased and is embarrassed  Age of menarche is a strong predictor of age at first intercourse  Late-maturing boys may be shunned  Early-maturing boys are socially popular and often sports heroes

 Defined as a sudden, uneven, and rather unpredictable jump in the size of almost every part of the body The Growth Spurt

 Increase occurs in bone length and density feet and fingers lengthen, then arms and legs, then torso  Weight gain becomes rapid  Height increase follows  Then more muscle Physical Changes…

 Primary sex characteristics—parts of the body that are directly involved in reproduction: vagina, uterus, testes, penis  Primary sex organs grow girls: uterus grows, vaginal lining thickens  menarche—first menstrual period boys: testes, penis, scrotal sac enlarge  spermarche—first ejaculation of seminal fluid Primary Sex Characteristics

Secondary Sex Characteristics  Secondary sex characteristics—body characteristics not directly involved in reproduction but indicating sexual maturity breasts  females accumulate fat  in both sexes, diameter of areola around nipples increases hair  voice lowers, especially in males  body hair becomes coarser and darker  new hair growth in armpits and in genital area

 Adolescence is generally healthy time  Minor childhood illnesses less common; major adult diseases rare  Health of adolescents is more likely to be harmed by their own actions Hazards to Health

Nutritional requirements are significantly increased during adolescence  Body mass doubles in males  Body fat content doubles in females (from 10 to 20%)  Adult eating habits are established

Check these numbers out…  Approximately 12% of adolescents between the ages of 12 and 17 are overweight AND…  60% of girls and 20% of boys are trying to lose weight

Nutritional surveys show that adolescents have the highest prevalence of nutrient deficiencies  Ca, Fe, Vitamins B 2, B 1, A and C  Dietary fat >33% of calories  French fries >25% of all vegetables

 Sexually active teenagers have higher rates of most common STIs—gonorrhea, genital herpes, syphilis, and chlamydia—than any other age group  Risk of exposure to HIV virus increases if a person is already infected with other STIs has more than one partner in a year does not use condoms during intercourse Sexually Transmitted Infections

STI Impact Despite Virginity Pledges  Brückner and Bearman (2005) A recent Yale University study concerning adolescent virginity pledges compared STI impact among teens who had taken a virginity pledge until marriage to those who did not take the pledge The pledges were documented in a 1995 National Longitudinal Study of Adolescent Health, a comprehensive in-home survey of more than 20,000 students in grades 7-12

The National Campaign to Prevent Teen Pregnancy (2003) Compared to delayed sexual activity, early sexual activity (young adolescents years old) is linked to:  Greater number of partners  Increased risk of teen pregnancy  Increased risk of STDs

 Younger adolescents within two years of beginning menarche are at increased risk for many complications because their bodies have not matured risks include spontaneous abortion, eclampsia, stillbirth, C-section, low birth weight women who have given birth before age 16 tend to be shorter and sicker as adults and live less long Teenage Pregnancies

 Older adolescents are at less physical risk but have their own set of problems after birth of baby, educational and vocational achievement slowed down babies have a higher risk of prenatal and birth complications than other babies problems are linked to culture and cohort

Sexual Abuse  Defined as the use of unconsenting person for one’s own sexual pleasure  Child sexual abuse—activity that arouses the adult and excites, shames, or confuses a person under age 16 abusers of adolescent girls—usually male relative or friend abusers of adolescent boys—usually male not in family

 Link between their occasional use and later drug abuse and addiction repeatedly found Characteristics: violence, early sexual activity, and school failure Drug use both cause and symptom of adolescent problem The Gateway Drugs

 Tobacco  Alcohol  Marijuana

Tobacco  Decreases food consumption  Interferes with absorption of nutrients  Reduces fertility  Most physically addictive drug of all

Smoking cigarettes during pregnancy…  Teenagers were more likely than women of any other age to smoke while pregnant  After experiencing a dramatic 20-percent decline in the first part of the decade, smoking rates among pregnant teenagers–unlike women of all other ages--increased by 5 percent from 1994 to 1999  The highest rate in 1999 (19 percent) was for women years of age

Alcohol  More harmful in adolescence  Correlates with abnormal brain development

Alcohol  Alcohol is a depressant yet we often feel lively after a couple of drinks… It gives this feeling by slowing down the brain centers that control judgments and inhibitions

Curious Effects  Memory  Sex  Hangover

Marijuana  Seriously slows down thinking processes, especially memory and abstract reasoning  May cause lack of motivation and indifference toward future

Marijuana  About 1 in 3 Americans has used marijuana at least once and approximately 10% of the population uses it on a regular basis

Marijuana  Triggers a mixture of effects that makes this drug difficult to classify… Like alcohol it has a depressant effect…  It relaxes, disinhibits, impairs motor coordination It is also a mild hallucinogen  It can slow the passage of time and amplify one’s sensitivity to colors, sounds, tastes, and smells

Credits  ppt#256,1,Adolescent Nutrition  Eating%20Disorder%20-%20Navazio.ppt#278,18