Adolescence: Biosocial Development

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Part V
Chapter Fourteen

• Adolescence Biosocial Development

Puberty Begins The Transformation of
Puberty Possible Problems
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Adolescence Biosocial Development

• the body changes of early adolescence rival
  those of infancy in speed and dramathe
  difference however is that adolescents are aware

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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

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Puberty Begins

• Puberty
• menarche
• a girls 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 boys 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

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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

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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

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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

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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

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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

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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

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Puberty Begins

• Genes
• hormonally and sexually girls are ahead by only a
  few months
• influence the timing of puberty in other ways as
  well

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Puberty Begins

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

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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

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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 childs
  parents are sick, addicted or divorced, or when
  the neighbor is violent and impoverished

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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

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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

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Nutrition

• the changes of puberty depend on nutrition, yet
  many adolescents are deficient in the necessary
  vitamins or minerals

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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

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Nutrition

• Body Image
• a persons 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

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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)

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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

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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

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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

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The Transformations of Puberty
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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

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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

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The Transformations of Puberty

• Sexual Maturation
• the second set of changes turns boys into men and
  girls into women

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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 mans beard and a womans breasts

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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

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The Transformations of Puberty

• Brain Development
• the limbic systemfear, emotional impulsematures
  before the prefrontal cortex (planning ahead,
  emotional regulation)

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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

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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 teenagers body, brain
  growth is uneven

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The Transformations of Puberty

• Neurological Advances
• with increased myelinaton, reactions become
  lightening fast
• pruning occurs, and the dopamine
  systemneurotransmitters that bring pleasureis
  very active
• before these advances are completeabout age
  25new 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

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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

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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
  severalwhile 80 are not bedeviled by problems

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Possible Problems

• Sex Too Soon
• adolescent sexuality can be problematic
• puberty occurs at young agesearly 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

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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)

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Possible Problems

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

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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

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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

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Possible Problems
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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

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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

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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

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Possible Problems

• Learning from experience
• generational forgetting
• the idea that each new generation forgets what
  the previous generation learned about harmful
  drugs