Kathleen Stassen Berger
Part V
Chapter Fourteen
Adolescence: Biosocial Development
Puberty Begins
The Transformation of Puberty
Possible Problems
Prepared by Madeleine Lacefield
Tattoon, M.A.
1
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…
2
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
3
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
4
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
5
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
6
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
7
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
8
Puberty Begins
• the average age is between 11 and
12
• but is still considered normal between
the ages of 8 and14
9
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
10
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
11
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
12
Puberty Begins
• Too Early, Too Late
– early maturing girls have lower selfesteem, more depression, poorer body
image, and boy-friends several years
older
– often isolated from their on-timematuring peers, and tend to associate
with older adolescents
13
Puberty Begins
• Too Early, Too Late
– cohorts are crucial for boys
– early-maturing boys live in stressful urban
neighborhoods and are likely to befriend lawbreaking, somewhat older boys
– ethnic differences in age of puberty can add to
ethnic tensions in high school, especially for
boys
14
Nutrition
…the changes of puberty depend on
nutrition, yet many adolescents are
deficient in the necessary vitamins or
minerals
15
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
16
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
17
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)
18
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
19
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
20
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
21
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
22
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
23
The Transformations of Puberty
• Sexual
Maturation
– the second set
of changes
turns boys into
men and girls
into women
24
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
25
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
26
The Transformations of Puberty
• Brain Development
– the limbic system—fear, emotional
impulse–matures before the prefrontal
cortex (planning ahead, emotional
regulation)
27
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
28
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
29
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
30
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
31
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)
32
Possible Problems
• Sexual Transmitted Infection (STI)
• a disease spread by sexual contact,
including syphilis, gonorrhea, genital
herpes, chlamydia, and HIV
33
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
34
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
35
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
36
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
37
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
38
Possible Problems
• generational forgetting
• the idea that each new generation
forgets what the previous generation
learned about harmful drugs
39