Adolescence: Biosocial Development

1
Part V
Chapter Fourteen

• Adolescence Biosocial Development

Puberty Begins The Transformation of
Puberty Possible Problems
2
Adolescence Biosocial Development

• the body changes of early adolescence rival
  those of infancy in speed and dramathe
  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 girls first menstrual period, signaling that
  she has begun ovulation. Pregnancy is
  biologically possible
• Spermarche
• a boys 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 childs
  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 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

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 mans beard and a womans 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 systemfear, emotional impulsematures
  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 teenagers body, brain
  growth is uneven

29
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 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 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

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