Slide 1
5—Physical Development in
Infancy
•
•
•
•
•
Body Growth and Change
The Brain
Sleep
Health
Summary
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 2
Body Growth and Change
• Growth Patterns
– Cephalocaudal pattern:
• The sequence in which the greatest growth occurs at
the top—the head—with physical growth in size,
weight, and feature differentiation gradually
working from top to bottom.
– Proximodistal pattern:
• The sequence in which growth starts at the center of
the body and moves toward the extremities.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 3
Body Growth and Change
Changes in Proportions of the Human Body
During Growth
• Refer to Figure 5.1
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 4
Body Growth and Change
• Infancy and Childhood
– Infancy
• The average North American newborn is 20 inches
long and weighs 7½ pounds.
• Most newborns lose 5% to 7% of their body weight
in the first several days of life.
• Newborns double their birth weight by the age of 4
months and nearly triple it by their first birthday, but
growth slows in the second year; by age 2, children
average 32 to 35 inches in height—nearly half their
adult height.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 5
Body Growth and Change
• Infancy and Childhood
– Early Childhood
• The percentage of increase in height and weight
decreases each year for preschoolers, and girls are
only slightly smaller and lighter than boys.
• Body fat declines slowly during preschool years;
girls have more fatty tissue than boys and boys have
more muscle tissue than girls
• Growth patterns vary due to heredity and
environmental experiences.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 6
Body Growth and Change
• Infancy and Childhood
– Early Childhood
• Physical problems, growth hormone deficiency, or
emotional difficulties may retard growth.
• Growth hormone deficiency: The absence or
deficiency of growth hormone produced by the
pituitary gland.
– Can be treated with injections of growth
hormone for several years.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 7
Body Growth and Change
• Infancy and Childhood
– Middle and Late Childhood (Ages 6 to 11)
• Slow, consistent growth averaging 2 to 3 inches a
year.
• Muscle mass increases; body fat decreases.
• Improved muscle tone and strength.
• Bones continue to harden.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 8
Body Growth and Change
• Puberty
– A period of rapid physical maturation involving
hormonal and bodily changes that take places in early
adolescence.
– Determinants of Puberty
• There are wide variations in onset and progression.
• Age of onset has been steadily dropping around the
world, with average age of menarche dropping 2 to
4 months per decade during the twentieth century.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 9
Body Growth and Change
– Determinants of Puberty (continued)
• Menarche: A girl’s first menstruation, with normal
age ranging from 9 to 15 years old.
• Timing for the emergence of puberty is hereditary,
but is influenced by environmental factors such as
health, weight, and stress.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 10
Body Growth and Change
– Determinants of Puberty (continued)
• Hormones: Powerful chemical substances secreted
by the endocrine glands and carried through the
body by the bloodstream.
• In puberty, secretion of key hormones is controlled
by the interaction of the hypothalamus, the pituitary
gland, and the gonads (sex glands).
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 11
Body Growth and Change
– Determinants of Puberty (continued)
• Adrenarche involves hormonal changes in the
adrenal glands (about ages 6 to 9).
• Gonadarche involves sexual maturation and the
development of reproductive maturity .
• Culmination of gonadarche in girls is menarche
(first menstruation), in boys is spermarche (the first
ejaculation of semen).
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 12
Body Growth and Change
– Determinants of Puberty (continued)
• Key hormonal changes of gonadarche are
androgens (main class of male hormones, e.g.,
testosterone) and estrogens (main class of female
hormones, e.g., estradiol).
• These hormones are present in both males and
females, but in different concentrations.
• Growth during puberty is facilitated by hormones
such as cortisol, testosterone, and estrogen.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 13
Body Growth and Change
Hormone Levels by Sex and Pubertal Stage
for Testosterone and Estradiol
• Refer to Figure 5.2
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 14
Body Growth and Change
• Puberty (continued)
– Weight and Body Fat
• Undernutrition can delay puberty: for menarche to
begin and continue, fat must make up 17% of a
girl’s body weight.
• Amenorrhea, an absence or suppression of
menstruation, occurs in anorexic adolescents and
females participating in some sports.
• Leptin, a hormone released by fat cells, signals the
adequacy of fat stores for reproduction and
maintenance of pregnancy at puberty.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 15
Body Growth and Change
• Puberty (continued)
– Growth Spurt
• Occurs approximately 2 years earlier for girls than
for boys.
• Mean beginning of the growth spurt in the U.S. is
age 9 for girls and age 11 for boys.
• Height and weight follow approximately the same
timetable, and 50% of adult body weight is gained
during adolescence.
• Girls increase in hip width, boys increase in
shoulder width.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 16
Body Growth and Change
Pubertal Growth Spurt
• Refer to Figure 5.3
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 17
Body Growth and Change
• Puberty (continued)
– Sexual Maturation
• The three most noticeable areas of sexual maturation
in boys include penis elongation, testes
development, and growth of facial hair.
• The two most noticeable areas of sexual maturation
in girls include breast enlargement and the
appearance of pubic hair.
• Menarche occurs late in the pubertal cycle.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 18
Body Growth and Change
• Puberty (continued)
– Body Image:
• Adolescents are preoccupied with their bodies.
• Girls are generally less happy than boys with their
bodies.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 19
Body Growth and Change
• Puberty (continued)
– Early and Late Maturation
• Early-maturing adolescents have more positive body
image than late-maturing adolescents, but by their
30s, late-maturing boys have a more positive
identity than early-maturing boys.
• Early-maturing girls have an increased vulnerability
to socioemotional problems.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 20
Body Growth and Change
Normal Range and Average Development of
Sexual Characteristics in Males and
Females
• Refer to Figure 5.4
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 21
Review and Reflect: Learning
Goal 1
• Discuss developmental changes in the body
– Review
• What are cephalocaudal and proximodistal patterns?
• What changes in height and weight take place in
infancy and childhood?
• What changes characterize puberty?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 22
Review and Reflect: Learning
Goal 1
– Reflect
• Did you experience puberty early, late, or on-time?
How do you think this affected your social
relationships and development?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 23
The Brain
• Brain Physiology
– The brain has two hemispheres.
– The forebrain, or top portion, is covered by a layer of
cells called the cerebral cortex, which is responsible
for 80% of the brain's volume; it is critical in
perception, thinking, language, and other functions.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 24
The Brain
• Brain Physiology (continued)
– Four lobes of the cortex:
• Frontal lobes: Govern voluntary movement,
thinking, personality, and intentionality or purpose.
• Occipital lobes: Control vision.
• Temporal lobes: Govern hearing, language
processing, and memory.
• Parietal lobes: Govern spatial location, attention,
and motor control.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 25
The Brain
The Human Brain’s Hemispheres
• Refer to Figure 5.5
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 26
The Brain
The Brain’s Four Lobes
• Refer to Figure 5.6
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 27
The Brain
• Brain Physiology (continued)
– Limbic System
• Hypothalamus (monitors eating, drinking, and sex)
• Pituitary gland (controls growth, regulates other
glands)
• Amygdala (governs emotions)
• Hippocampus (governs memory and emotion)
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 28
The Brain
• Brain Physiology (continued)
– Neuron
• Nerve cell that handles information processing at the
cellular level.
• Axons send electrical signals away from the central
part of the neuron, across synaptic gaps, via
chemical substances called neurotransmitters.
• Dendrites of different neurons receive the signals.
• Myelin sheath: Layer of fat cells that helps
impulses travel faster along the axon.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 29
The Brain
The Neuron
• Refer to Figure 5.7
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 30
The Brain
• Brain Physiology (continued)
– Neural circuits are clusters of neurons that work
together to handle particular types of information.
• The neural circuit for attention and working memory
uses the neurotransmitter dopamine and lies in the
prefrontal cortex.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 31
The Brain
The Prefrontal Cortex
• Refer to Figure 5.8
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 32
The Brain
• Brain Physiology (continued)
– Lateralization
• Specialization of function in one hemisphere of the
cerebral cortex or the other.
• Complex thinking requires both hemispheres.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 33
The Brain: Infancy
– Brain development occurs extensively in utero.
– Because of the extensive brain development during
infancy, the infant’s head must be protected.
• Shaken baby syndrome: Damage to brain from
shaking a baby, includes brain swelling and
hemorrhaging.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 34
The Brain: Infancy
• Early Experience and the Brain
– Depressed brain activity has been found in children
who grow up in a deprived environment (Cicchetti,
2001), and it’s possible the effects are irreversible.
– Neuroscientists believe that what wires the brain is
repeated experience:
• Before birth, genes direct wiring patterns.
• After birth sensory and environment input shape
neural connections.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 35
The Brain: Infancy
Early Deprivation and Brain Activity
• Refer to Figure 5.9
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 36
The Brain: Infancy
• Changing Neurons
– Myelination, the process of encasing axons with fat
cells, begins prenatally and continues after birth.
– Among the most dramatic changes in the brain in the
first 2 years of life are the increases in synaptic
connections, with synaptic blooming and pruning.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 37
The Brain: Infancy
• Changing Structures
– The frontal lobe is immature at birth, but increased
myelination and neural connections during the first year
enhance the ability to regulate physiological states and
gain more control over reflexes.
– 2 months: development of motor control centers allow
reaching and grabbing.
– 4 months: neural connections for depth perception
begin to form.
– 12 months: speech centers ready to produce language.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 38
Infancy
The Development of Dendritic Spreading
• Refer to Figure 5.10
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 39
The Brain: Infancy
Synaptic Density in the Human Brain from
Infancy to Adulthood
• Refer to Figure 5.11
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 40
The Brain: Childhood
– Brain growth is slower than in infancy, but the brain
and the head grow faster than other parts of the body.
• Increase, due to myelination (which is not complete
until the end of middle or late childhood), in number
and size of dendrites.
• Most rapid growth from age 3 to 6 is in frontal lobe
areas (planning and organizing new actions and
maintaining attention to tasks).
• Most rapid growth from age 6 through puberty is in
temporal and parietal lobes, especially for language
and spatial relations.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 41
The Brain: Adolescence
• Adolescents process emotional information primarily in
the amygdala (emotion-processing area) rather than in the
frontal lobe (higher-level reasoning and thinking area); the
reverse occurs in adults.
• The adolescent prefrontal cortex is not yet developed to
control strong emotions (Nelson, 2003).
• Areas of the limbic system involved with reward and
pleasure lead adolescents to seek novelty and to need
higher levels of stimulation to experience pleasure.
• Slow development of prefrontal cortex means a lack of
cognitive skill for controlling pleasure seeking, which may
explain increased risk-taking and other problems.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 42
Review and Reflect: Learning
Goal 2
• Describe how the brain changes
– Review
• What is the nature of brain physiology?
• How does the brain change in infancy?
• What characterizes the development of the brain in
childhood?
• How does the brain change in adolescence and how
might this change be linked to adolescent behavior?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 43
Review and Reflect: Learning
Goal 2
• Reflect
– Claims are made that elementary and secondary
education should be brain-based. Some journalists
suggest that educators look to neuroscientists for
answers about how best to teach children and
adolescents. Such statements are speculative and far
removed from what neuroscientists know. Find an
article on brain-based education in a magazine or on the
Internet. Use your critical thinking skills to evaluate the
article’s credibility. Does the author present research
evidence to support the link between neuroscience and
the brain-based method being recommended? Explain.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 44
Sleep
• Sleep restores, replenishes, and rebuilds the brain and
body.
• Some neuroscientists believe that sleep allows neurons that
have been used during waking to shut down and repair
themselves.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 45
Sleep: Infancy
– Newborns sleep 16 to 17 hours a day, although some
sleep more and others sleep less.
– By age 1 month most infants sleep longer at night.
– By age 4 months their patterns are closer to adult sleep
patterns.
– There are cultural variations in sleep patterns.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 46
Sleep: Infancy
– REM Sleep
• Adults spend about one-fifth of their night in REM
sleep and it usually appears about 1 hour after nonREM sleep.
• About one-half of an infant’s sleep is REM sleep,
and infants often begin their sleep cycle with REM
sleep rather than non-REM sleep.
• REM sleep might promote the brain’s development
in infancy.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 47
Sleep: Infancy
Sleep Across the Human Life Span
• Refer to Figure 5.12
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 48
Sleep: Infancy
– Shared Sleeping
• Sharing a bed with a mother is a common practice in
many cultures.
• Shared sleeping remains a controversial issue.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 49
Sleep: Infancy
– SIDS
• Sudden infant death syndrome (SIDS)—A
condition that occurs when an infant stops breathing,
usually during the night, and suddenly dies without
an apparent cause.
• SIDS decreases when infants sleep on their backs.
• Risk factors include low birth weight, a sibling who
has died of SIDS, sleep apnea, being African
American or Eskimo, lower socioeconomic status,
exposure to cigarette smoking, and soft bedding.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 50
Sleep: Childhood
– Most young children sleep through the night and have
one daytime nap, although they may try to drag out
their bedtime routine.
– Sixth-graders go to bed an hour later than secondgraders and report more daytime sleepiness.
– Sleep problems: Nightmares (frightening dreams that
awaken the sleeper) and night terrors (sudden arousal
from sleep with intense fear and physiological
reactions) are common sleep problems.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 51
Sleep: Adolescence
• Adolescents sleep an average of 9 hours and 25 minutes
when allowed to sleep as long as they like, but most get
much less sleep, which creates sleep debt.
• Older adolescents are sleepier than younger adolescents
due to hormonal phase shift of biological clocks.
• Melatonin, a hormone that prepares the body for sleep, is
secreted an hour later in older adolescents than in younger
adolescents.
• Starting school an hour later has improved tests scores and
decreased discipline problems, illness, and depression for
students in Edina, MN.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 52
Review and Reflect: Learning
Goal 3
• Summarize how sleep patterns change as
people develop
– Review
• How can sleep be characterized in infancy?
• What changes occur in sleep during childhood?
• How does adolescence affect sleep?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 53
Review and Reflect: Learning
Goal 3
– Reflect
• Did your sleep patterns start to change when you
became an adolescent? Have they changed since you
went through puberty? If so, how?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 54
Health
• Illnesses and Injuries among Children and
Adolescents
– Early Childhood:
• Vaccines have nearly eradicated many diseases.
• Birth defects, cancer, and heart disease are the
disorders that are most likely to be fatal to children
under age 5 today.
• Accidents are the leading cause of death in young
children.
• Parental smoking puts children at risk for respiratory
problems and vitamin C deficiency.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 55
Health
Main Causes of Death in Children 1 Through
4 Years of Age
• Refer to Figure 5.13
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 56
Health
• Illnesses and Injuries among Children and
Adolescents (continued)
– Middle and Late Childhood:
• Mostly a time of excellent health.
• Motor vehicle accidents are the most common cause
of severe injury and death; this can be reduced by
use of seat belts.
• Cancer is the second leading cause of death for this
age group.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 57
Health
• Illnesses and Injuries among Children and
Adolescents (continued)
– Adolescence:
• Leading cause of death is accidents, with alcohol
involved in 50% of motor vehicle fatalities.
• Homicide is second leading cause of death, and
suicide is third.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 58
Health
• Health, Illness, and Poverty among the
World’s Children
– 17% of children in the U.S. live in poverty, and 7%
have no source of routine health care.
– Lead is linked to lower intelligence and achievement,
and to ADHD.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 59
Health
• Health, Illness, and Poverty Among the
World’s Children (continued)
– The poor are a majority in 20% of the world nations.
– A leading cause of child death in impoverished
countries is diarrhea produced by dehydration;
immunization programs help reduce death by measles,
tetanus, and whooping cough.
– HIV/AIDS has dramatically increased for these
children and is a major cause of death.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 60
Health
• Nutrition and Eating Behavior: Infancy
– The importance of adequate energy and nutrient intake
consumed in a loving and supportive environment
during the infant years cannot be overstated (Samour,
Helm, & Lang, 2000).
– Breast-feeding versus bottle-feeding: Benefits include
appropriate weight gain, fewer allergies, prevention and
reduction of diseases, denser bones in childhood and
adulthood, reduced childhood cancer, lower incidence
of SIDS, and better visual acuity.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 61
Health
• Nutrition and Eating Behavior: Infancy
– Breast-feeding versus Bottle-feeding
• Avoid breast-feeding when the mother has AIDS,
tuberculosis, or is taking a drug that might not be
safe for the infant.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 62
Health
Trends in Breastfeeding in the United States:
1970–2001
• Refer to Figure 5.14
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 63
Health
• Nutrition and Eating Behavior: Infancy
– Malnutrition in Infancy
• Marasmus: A wasting away of body tissues in the
infant’s first year, caused by severe protein-calorie
deficiency.
• Kwashiorkor: A condition caused by a deficiency
in protein in which the child’s abdomen and feet
become swollen with water.
• The effects of nutrition in infancy extend at least
into early childhood
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 64
Health
• Nutrition and Eating Behavior: Childhood
• Children in many developing countries face
malnutrition and starvation daily.
• In the U.S. 11 million preschool children are
malnourished, putting their health at risk;
malnutrition is associated with problem behaviors as
they get older.
• Special Supplemental Nutrition Program for
Women, Infants, and Children (WIC) provides
nutrition and counseling on nutrition to low-income
participants.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 65
Health
• Nutrition and Eating Behavior: Childhood
– Health and Unhealthy Eating
• Since the late 1970s, eating habits have shifted from
healthy foods to salty snacks, soft drinks, pizza, and
to high-fat beef and pork.
• Eating high-fat fast foods damages the heart.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 66
Health
• Nutrition and Eating Behavior: Childhood
– Obesity
• Energy requirements depend on physical activity
and basal metabolism rate (BMR).
• American eating trends are producing increasing
numbers of overweight children and adults.
• Obesity increases the risk of developing medical and
psychological problems.
• Experts recommend combining proper diet with
exercise and behavior modification.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 67
Health
Relation of Being Overweight in Childhood
with Being Overweight in Adulthood
• Refer to Figure 5.15
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 68
Health
• Nutrition and Eating Behavior: Adolescence
• Adolescent girls want to weigh less.
• Eating disorders are linked with negative body
disorders, sexual activity, and pubertal transition.
• Anorexia nervosa is an eating disorder that
involves the relentless pursuit of thinness through
starvation.
• Bulimia nervosa is an eating disorder in which the
individual consistently follows a binge-and-purge
eating pattern.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 69
Health
Percentage of Overweight U.S. Adolescent
Boys and Girls in Different Ethnic Groups
• Refer to Figure 5.16
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 70
Health
• Nutrition and Eating Behavior: Adolescence
– Exercise:
• Although exercise is linked with many aspects of
physical and mental health, U.S. adolescents
exercise less than their counterparts in most other
countries.
• As age increases, physical activity decreases.
• Television watching is linked with low activity and
obesity.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 71
Health
Percentage of Children Involved in Daily
Physical Education Programs in the United
States from 1969 to 1999
• Refer to Figure 5.17
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 72
Health
• Nutrition and Eating Behavior: Adolescence
– Substance Use:
• Cigarette smoking begins in childhood and
adolescence, and alcohol abuse begins in high
school or college.
• The earlier use begins, the greater the detrimental
long-term effects.
• Trends in drug use: Declined in 1980s, increased in
1990s; the U.S. has the highest rate of adolescent
drug use of any industrialized nation.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 73
Health
Trends in Drug Use by U.S. Eighth-, Tenth-,
and Twelfth-Grade Students
• Refer to Figure 5.18
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 74
Health
• Nutrition and Eating Behavior: Adolescence
– Substance Use (continued)
• Alcohol use has declined over the past 10 years.
• Cigarette smoking is also decreasing; smoking in
adolescence causes permanent genetic changes in
the lungs.
• Parents and peers play important roles in preventing
adolescent drug abuse.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 75
Review and Reflect: Learning
Goal 4
• Characterize health in childhood and
adolescence
– Review
• What are the key health problems facing children?
• What are some important aspects of children’s
nutrition and eating behavior?
• What role does exercise play in children’s
development?
• What is the nature of substance use in adolescence?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 76
Review and Reflect: Learning
Goal 4
– Reflect
• What were your eating habits like as a child? In
what ways are they similar to or different from your
current eating habits? Were your early eating habits
a forerunner of whether or not you have weight
problems today?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 77
Summary
• The cephalocaudal pattern is the sequence in
which the greatest growth occurs at the top—the
head—and gradually proceeds from top to bottom.
• The proximodistal pattern is the sequence in
which growth starts at the center of the body and
moves toward the extremities.
• Height and weight increase rapidly in infancy,
then take a slower course in childhood.
• Puberty is a rapid maturation involving hormonal
and body changes that occur primarily in early
adolescence.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 78
Summary
• Each hemisphere of the brain has four lobes (frontal,
occipital, temporal, and parietal).
• Communication between neurons occurs through the
release of neurotransmitters.
• Myelination begins prenatally and continues after birth,
with enormous increase in synaptic connections during
infancy.
• During early childhood, the brain and head grow more
rapidly than other parts of the body.
• Later development of frontal lobes and earlier dominance
of the amygdala play an important role in adolescent risktaking behavior.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 79
Summary
• Newborns sleep 16 to 17 hours a day; by 4 months
most infants have sleep patterns similar to adults.
• Infants have more REM sleep than older children
and adults.
• Sleeping arrangements vary across cultures.
• Young children sleep through the night and have a
daytime nap.
• Adolescent sleep patterns change due to hormonal
changes that shift their biological clocks.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 80
Summary
• In recent decades, vaccines have eradicated many
diseases.
• Today the most fatal childhood disorders are birth
defects, cancer, and heart disease.
• Accidents are the number one cause of death in
young children.
• The leading causes of death for adolescents are
accidents, homicide, and suicide.
• Poverty affects the health of children around the
world.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 81
Summary
• Diarrhea caused by dehydration is a major cause
of death for children in poor countries, and
HIV/AIDS has increased for those children
dramatically.
• Adequate energy intake is critical for infants, and
breast-feeding is usually recommended over
bottle-feeding.
• Marasmus and kwashiorkor are diseases caused by
severe malnutrition.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 82
Summary
• Nutritional concerns for children focus on fat
content and obesity, with more than 20% of U.S.
children being overweight and 10% being obese.
• Obesity increases risks for medical and
psychological problems.
• In adolescence, nutrition and being overweight are
problems, as are anorexia nervosa and bulimia
nervosa.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 83
Summary
• Most children and adolescents in the U.S. do not
get enough exercise.
• The U.S. has the highest rate of adolescent drug
use of any industrialized nation, and special
concerns are alcohol and cigarette smoking.
• Parents and peers play important roles in
preventing drug abuse in adolescents.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..