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

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

3. 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

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

5.  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

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

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

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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

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

17.  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…

18.  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

19. 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

20.  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

21. 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

22. 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

23. 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

24.  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

25. 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

26. The National Campaign to Prevent Teen Pregnancy (2003) Compared to delayed sexual activity, early sexual activity (young adolescents 12-14 years old) is linked to:  Greater number of partners  Increased risk of teen pregnancy  Increased risk of STDs

27.  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

28.  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

29. 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

30.  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

31.  Tobacco  Alcohol  Marijuana

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

33. 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 18-19 years of age

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

35. 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

36. Curious Effects  Memory  Sex  Hangover

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

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

39. 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

40. Credits  http://www.aecom.yu.edu/family/presentations/adolnutr. ppt#256,1,Adolescent Nutrition  http://mcb.berkeley.edu/courses/mcb135e/lecture38- Eating%20Disorder%20-%20Navazio.ppt#278,18