Chapter Fourteen

1. Chapter Fourteen Adolescence: Biosocial Development

2. 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 Normally, body changes begin to appear between ages 8 and 14 It’s hard to prepare without knowing what changes will be and when they’ll appear individual may grow a little taller and put on some weight Menarche -for girls, puberty begins with growth of nipples, first pubic hair, widening of hip and menstrual period Spermarche -for boys, puberty begins with testes, growth of initial pubic hair, growth of penis and first ejaculation of seminal fluid

3. 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 At puberty, the pituitary gland activates the gonads, or sex glands (ovaries in females, testes in males) One hormone in particular, GnRH, causes increased production of estrogen in females and testosterone in males Hormones

4. Direct Effects on Emotions Hormonal levels correlate with quick shifts in emotional extremes For boys this increase precipitates thoughts about sex and masturbation For girls hormonal changes of increase happiness in the middle of the menstrual cycle and sadness or anger at the end Example: a 14-year-old teenage boy who can not control his sexual arousal and/or thoughts about sex and masturbation when he sees an attractive image or opposite sex. 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

5. 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 violent or impoverished neighborhood unrelated man living in the home Some studies have concluded early onset of puberty is partly genetic. parents reach puberty early also marry early more likely those parents will be undereducated, depressed, angry and divorced their children will live with conflicted divorce-prone parents

6. 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 Low self-esteem of off-time maturation lingers Early-maturing girls become mothers sooner Late-maturing boys marry later and are less likely to be leaders

7. 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

8. 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

9. Need for good, healthy calories is greater due to growth spurt many adolescents become fat and flabby—due not to excess food, but lack of exercise Adolescents generally eat enough but not the right foods snack with friends too much fat, sugar, empty calories; too little calcium Only one in five U.S. high school seniors consumes RDI of five servings of fruits and vegetables Inadequate milk consumption is troubling, as calcium is major contributor to bone growth one-half adult bone mass acquired during adolescence Fewer than half of all teenagers consume RDI of iron females do not get enough iron, while menstrual cycle depletes iron; therefore, may become anemic Nutritional deficits sometimes arise from distorted body image Body Image—person’s concept of how his or her body appears developing a healthy body image is an integral part of becoming an adult negative-self appraisal has a major impact on self-esteem Poor Nutrition

10. With puberty occurring earlier than it used to in the United States, and marriage later, long period between first sexual urges and marriage More than 25 percent of teens are sexually active by age 14; about one-half active by high school graduation Early sexual activity correlates with depression and drug use Sexually active teenagers have higher rates of most common STDs—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 STDs has more than one partner in a year does not use condoms during intercourse Sex Too Soon

11. 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 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 Teenage Pregnancies

12. 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 Tobacco decreases food consumption interferes with absorption of nutrients reduces fertility most physically addictive drug of all Alcohol more harmful in adolescence correlates with abnormal brain development Marijuana seriously slows down thinking processes, especially memory and abstract reasoning may cause lack of motivation and indifference toward future The Gateway Drugs

13. Almost every teenager tries one of the gateway drugs by high school graduation, most have tried all three experimentation happening earlier than previously Experimentation and regular use daily use and abuse increases throughout late adolescence National culture makes a difference In Europe, adolescents show increased drug use adolescent girls in United States as likely to smoke as adolescent boys; in Asia and African few women smoke drug use changes in frequency, composition, mode of delivery, and in form Patterns of Adolescent Drug Use