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Part V

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  1. Part V Chapter Fourteen Adolescence: Biosocial Development Puberty Begins The Transformation of Puberty Possible Problems Prepared by Madeleine Lacefield Tattoon, M.A.

  2. Adolescence: Biosocial Development …the body changes of early adolescence rival those of infancy in speed and drama…the difference however is that adolescents are aware…

  3. Puberty Begins • Puberty • the time between the first on rush of hormones and full adult physical development • puberty usually last three to five years • many more years are required to achieve psychosocial maturity

  4. Puberty Begins • Menarche • a girl’s first menstrual period, signaling that she has begun ovulation. Pregnancy is biologically possible • Spermarche • a boy’s first ejaculation of sperm. Erections can occur as early as infancy, but ejaculation signals sperm production. may occur during sleep or via direct stimulation

  5. Puberty Begins • Hormones • organic chemical substances that are produced by one body tissue • are conveyed via the bloodstream to affect some physiological function. • various hormones influence thoughts, urges, emotions, and behavior

  6. Puberty Begins • Pituitary • a gland that, in response to a signal from the hypothalamus, produces many hormones, including those that regulate growth and control other glands, among them the adrenal and sex glands • Adrenal glands • two glands, located above the kidneys, that produce hormones (including the “stress hormones” epinephrine [adrenaline] and norepinephrine) • HPA axis (leads from brain to body to behavior) • the hypothalamus-pituitary-adrenal axis, a route followed by many kinds of hormones to trigger the changes of puberty and to regulate stress, growth, sleep, appetite, sexual excitement, and various other bodily changes

  7. Puberty Begins • Sex Hormones • Gonads • paired sex glands (ovaries in females, testicles in males) that produce hormones and gametes • Estradiol • a sex hormone, considered the chief estrogen. Females produce more estradiol than males do • Testosterone • a sex hormone, the best known of the androgens (male hormones); secreted in far greater amounts by males then by females

  8. Puberty Begins • Adolescents are best known for emotional and sexual behaviors • testosterone levels stimulates rapid arousal of emotions, especially anger • hormonal bursts lead to quick emotional extremes • for many boys, the increase in androgens causes sexual thoughts and a desire to masturbate • for many girls, the fluctuating estrogens increase happiness in the middle of the menstrual cycle (at ovulation) and sadness or anger at the end

  9. Puberty Begins • the average age is between 11 and 12 • but is still considered normal between the ages of 8 and14

  10. Puberty Begins • Genes • genes on the sex chromosomes markedly affect the onset of puberty • on average girls are about two years ahead of boys in height

  11. Puberty Begins • Body Fat • genetic differences are apparent only when every child is well fed • stocky individuals begin puberty before those with thinner builds • in both sexes chronic malnutrition delays puberty

  12. Puberty Begins • Stress • the production of many hormones is directly connected to stressful experience via the HPA axis • puberty tends to arrive earlier if a child’s parents are sick, addicted or divorced, or when the neighbor is violent and impoverished

  13. Puberty Begins • Too Early, Too Late • early maturing girls have lower self-esteem, more depression, poorer body image, and boy-friends several years older • often isolated from their on-time-maturing peers, and tend to associate with older adolescents

  14. Puberty Begins • Too Early, Too Late • cohorts are crucial for boys • early-maturing boys live in stressful urban neighborhoods and are likely to befriend law-breaking, somewhat older boys • ethnic differences in age of puberty can add to ethnic tensions in high school, especially for boys

  15. Nutrition …the changes of puberty depend on nutrition, yet many adolescents are deficient in the necessary vitamins or minerals

  16. Nutrition • Diet Deficiencies • few than ½ of all teenagers consume the recommended daily dose of iron • more girls are anemic due to iron depletion during menstruation • ½ of adult bone mass is acquired from age10-20, yet few adolescents consume enough calcium

  17. Nutrition • Body Image • a person’s idea of how his or her body looks • puberty alters the entire body making it impossible for teenagers to welcome every change • girls diet to become thinner • boys want to look taller and stronger

  18. Nutrition • Body Image • stressed teenagers eat erratically or ingest drugs hoping to lose weight • 12% of U.S. teenagers are overweight • 2/3 (62%) of U.S. girls and almost 1/3 of the boys are trying to lose weight according to survey of 14,000 school students (June 2006)

  19. The Transformations of Puberty • every body part changes during puberty • transformation from a child into an adult is traditionally divided in two parts: growth and sexuality • the third division is the transformation of the brain

  20. The Transformations of Puberty • Growing Bigger and Stronger • growth spurt • the relatively sudden and rapid physical growth that occurs during puberty… each body part increases size on a schedule; weight usually precedes height, and the limbs precede the torso

  21. The Transformations of Puberty • Growing Bigger and Stronger • growth proceeds from the extremities to the core • fingers and toes lengthen before the hands and feet • the torso is the last body part to grow • temporarily big-footed, long-legged, and short-waisted

  22. The Transformations of Puberty • Sequence: Weight, Height, Muscles • bones lengthen and harden • children eat more and gain weight • when, where, and how much weight depends on heredity, diet, exercise and gender • girls gain much more fat than boys • by age 17 the average girl has twice as much as her male classmate

  23. The Transformations of Puberty • Other body changes • organs grow and become more efficient • lungs triple in weight • adolescents breathe more deeply and slowly • the heart doubles in size and beats more slowly • blood pressure and volume both increase • weight and height increase before the growth of muscles and internal organs

  24. The Transformations of Puberty • Sexual Maturation • the second set of changes turns boys into men and girls into women

  25. The Transformations of Puberty • Primary Sex Characteristics • the parts of the body that are directly involved in reproduction, including the vagina, uterus, ovaries, testicles, and penis • Secondary Sex Characteristics • physical traits that are not directly involved in reproduction but that indicate sexual maturity, such as a man’s beard and a woman’s breasts

  26. The Transformations of Puberty • Sexual Activity • fantasizing, flirting, hand-holding, displaying, and touching are all done in particular ways to reflect gender, availability, and culture • hormones trigger thoughts and emotions, but the social context shapes through into enjoyable fantasies, shameful preoccupations, frightening impulses, or actual contact

  27. The Transformations of Puberty • Brain Development • the limbic system—fear, emotional impulse–matures before the prefrontal cortex (planning ahead, emotional regulation)

  28. The Transformations of Puberty • Uneven Growth • the immature prefrontal cortex may allow “troublesome adolescent behavior” • adolescents are capable of rational thinking • as in the rest of the teenager’s body, brain growth is uneven

  29. The Transformations of Puberty • Neurological Advances • with increased myelinaton, reactions become lightening fast • pruning occurs, and the dopamine system–neurotransmitters that bring pleasure–is very active • before these advances are complete–about age 25, acquisition of new ideas, words, memories, values are more likely to endure than those learned later, after brain links are more firmly established

  30. The Transformations of Puberty • Body Rhythms • brain rhythms affect body rhythms • the brain of every living creature responds to natural changes • puberty alters biorhythms • sleep patterns are irregular

  31. Possible Problems • Sex Too Soon • puberty occurs at young ages—early sexual experiences correlate with depression and drug use • raising a child has become more complex, which means that teenage pregnancy is no longer welcomed or expected • sexually transmitted infections are more common and dangerous

  32. Possible Problems • Teenage Pregnancy • ½ as common as it was 20 years ago in the U.S. • abortion rate had also decreased • contraception use is higher and teen intercourse is lower ( February 2005)

  33. Possible Problems • Sexual Transmitted Infection (STI) • a disease spread by sexual contact, including syphilis, gonorrhea, genital herpes, chlamydia, and HIV

  34. Possible Problems • Protection • regular medical care can prevent and treat STIs • almost every teenager knows that pregnancy and STIs can be prevented • tend to confuse appearance and reality; well-dressed partners could have STIs

  35. Possible Problems • Child Sexual Abuse • any erotic activity that arouses an adult and excites, shames, or confuses a child, whether or not the victim protests and whether or not genital contact is involved

  36. Possible Problems • Drug Use and Abuse • innocence is reflected in drug use • few adolescents imagine becoming addicted • worldwide most young people use at last one drug before age 18

  37. Possible Problems • Variations by Nation, Gender, and Ethnicity • drug use varies from nation to nation • laws and family practices are a part of the reason for these variations • gender differences are apparent for most drugs, with boys having higher rates of use than girls

  38. Possible Problems • Harm from Drugs • adolescents think adults exaggerate the harm of teen drug use • drugs interfere with healthy eating and digestion • drugs appear to make problems better, which leads to abuse and addition

  39. Possible Problems • generational forgetting • the idea that each new generation forgets what the previous generation learned about harmful drugs