1. Adolescence: Biosocial Development
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 onrush 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 Puberty menarche spermarche
a girl’s first menstrual period, signaling that she has begun ovulation. Pregnancy is biologically possible, but ovulation and menstruation are often irregular for years after menarche
spermarche
a boy’s first ejaculation of sperm. Erections can occur as early as infancy, but ejaculation signals sperm production. Spermache occurs during sleep (in a “wet dream”) or via direct stimulation

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

6. Puberty Begins pituitary adrenal glands
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 estradiol testosterone
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 Sudden emotions
behaviors that adolescents are best known for are emotional and sexual
testosterone at high or accelerating levels stimulates rapid arousal of emotions, especially anger
hormonal bursts lead to quick emotional extremes (despair, ecstasy)
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 When will puberty Start?
…the average age of onset varies…
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
Genes
hormonally and sexually girls are ahead by only a few months
influence the timing of puberty in other ways as well

12. Puberty Begins Body Fat
genetic differences are apparent only when every child is well fed
stocky individuals begin puberty before those with thinner builds

13. Puberty Begins Body Fat
in both sexes chronic malnutrition delays puberty
secular trend
a term that refers to the earlier and greater growth of children due to improved nutrition and medical care over the last two centuries

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

15. Puberty Begins Too Early, Too Late
no one wants to be early or late, particularly too early for girls and too late for boys
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

16. 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

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

18. 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

19. 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

20. Nutrition
Body Image
stressed teenagers eat erratically or ingest drugs hoping to lose weight
Adolescents can give up, becoming lazy and fat instead of strong and thin
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 (MMWR June 9,2006)

21. 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

22. 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

23. 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

24. The Transformations of Puberty

25. 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 mush as her male classmate

26. 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

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

28. The Transformations of Puberty
Sexual Body Changes
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

29. 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

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

31. The Transformations of Puberty
Caution Versus Thrills
interdisciplinary research is needed to integrate neurology and psychology
caution is needed, lest “incomplete brain development [becomes] an explanation for just about everything about teens that adults have found perplexing, from sleep patterns to risk taking and mood swings”

32. 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

33. 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–new connections between one synapse and another ease acquisition of new ideas, words, memories, values acquired during adolescence are more likely to endure than those learned later, after brain links are more firmly established

34. 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

35. Possible Problems
growth and sexual awakening, emotional intensity and hormonal rushes, all can be quite wonderful
maturation can cause problems
20% of young people have one problem or several—while 80% are not bedeviled by problems

36. Possible Problems Sex Too Soon adolescent sexuality can be problematic
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

37. 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 (MMWR, February 4th 2005)

38. Possible Problems Sexual Infections sexual transmitted infection (STI)
a disease spread by sexual contact, including syphilis, gonorrhea, genital herpes, chlamydia, and HIV

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

40. Possible Problems Sexual Abuse 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

41. Possible Problems

42. 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

43. 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

44. 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

45. Possible Problems Learning from experience generational forgetting
the idea that each new generation forgets what the previous generation learned about harmful drugs