LIFESPAN DEVELOPMENT

1
LIFE-SPAN DEVELOPMENT
3
A Topical Approach to
Physical Development and Biological Aging
John W. Santrock
2
Patterns of Growth
Body Growth and Change

• Cephalocaudal patterngrowth occurs first at the
  topthe headand gradually proceeds from top to
  bottom
• Proximodistal patterngrowth starts at the center
  of the body and moves toward the extremities

3
Height and Weight in Infancy and Childhood
Body Growth and Change
4
Puberty
Body Growth and Change

• A gradual process involving multiple
  distinguishing events.
• Physical, psychological and social changes.
• Two phases
• Adrenarche - changes in adrenal glands
• Gonardarche
• Menarche
• Spermarche

5
Determinants of Puberty
Body Growth and Change

• Heredity
• Hormones
• Androgens
• Estrogens
• Weight and Body Fat
• Environmental influences secular trend

6
Hormone Levels by Sex and Pubertal Stage for
Testosterone and Estadiol
Body Growth and Change
7
Pubertal Growth Spurt
Body Growth and Change
8
Development of Sexual Characteristics - Males
9
Development of Sexual Characteristics - Females
10
Body Image in Puberty
Body Growth and Change

• Adolescents become preoccupied by bodies
• Girls less satisfied, boys more satisfied
• Early and Late Maturation
• Early boys more positive
• Late boys more positive identity by 30s
• Early girls positive but potential problems
• Late girls more positive about bodies in late
  adolescents

11
Early Adulthood
Body Growth and Change

• Many reach peak of muscle tone and strength in
  late teens and twenties
• Decline in the thirties

12
Middle Adulthood
Body Growth and Change

• Lose height, gain weight
• Physical appearance concerns in youth-oriented
  culture
• Strength, bone density, flexibility decrease
• Cholesterol, blood pressure rise
• Sexuality changes
• Climactericfertility declines
• Menopausewomans menstrual periods cease

13
Late Adulthood
Body Growth and Change

• Variability in physical declines
• Socioeconomic status is a big factor
• Continue to lose height, lose weight
• Weight lifting can slow muscle decrease
• Wrinkles continue, age spots
• Lungs start to stiffen around age 55
• Blood pressure can rise

14
Changes in Body Composition with Age
Body Growth and Change
15
Brain Physiology
The Brain

• Neuronnerve cell that handles information
  processing at the cellular level.
• Parts of the neuron
• Dendrites receive info from other neurons
• Soma contains nucleus
• Axon transmits message to other neurons via
  neurotransmitters

16
The Neuron
The Brain
17
Cerebral Cortex

• Cerebral cortex makes up 80 of brain volume and
  is critical to perception, thinking and
  language.
• Lateralizationspecialization of functions in one
  hemisphere of cerebral cortex

18
The Human Brains Hemispheres
The Brain
19
The Brains Four Lobes
The Brain
20
Functions of Lobes of the Cortex
The Brain
Frontal lobes
Involved in voluntary movement, thinking,
personality, and intentionality or purpose
Occipital lobes
Function in vision
Temporal lobes
Active role in hearing, language processing, and
memory
Parietal lobes
Roles in registering spatial location, attention,
and motor control
21
The Brain in Infancy
The Brain

• Enriched early experience can enhance brain
  functioning
• Neurons change
• Myelination growth of fatty insulation around
  axons improves neural efficiency
• Rapid growth and pruning of dendrites and
  connections
• Left hemisphere active as infants learn language
• Frontal cortex develops to allow motor control

22
Dendritic Spreading
23
Changes in Synaptic Density with Age
24
The Brain in Childhood
The Brain

• During early childhood, the brain and head grow
  more rapidly than any other part of the body
• Some of brains increase due to myelination and
  some due to increase in number and size of
  dendrites

25
Brain and Body Growth
26
The Brain in Adolescence
The Brain

• Spurts in EEG activity seem to occur at about 9,
  12, 15, and 18 to 20 years
• May signal changes in cognitive development
• Pruning of synapses continues into late
  adolescence
• Amygdala and hippocampus increase
• May affect emotional development

27
The Shrinking, Slowing Brain
The Brain

• General slowing of function in brain and spinal
  cord begins in middle adulthood and accelerates
  in late adulthood
• Reductions in neurotransmitters
• Acetylcholine - memory
• Dopamine - planning, motor activities
• GABA - vision, thinking

28
The Adapting Brain

• Grows new brain cells throughout life
• Extent depends on environment
• Dendrite growth continues through 70s
• More myelination between frontal cortex and
  limbic system facilitates reflection
• Less lateralization with age

29
Sleep Infancy
Sleep

• Average 16-17 hours a day
• Ranges from 10 to 21
• More REM sleep than any other time of life
• Shared sleeping with parents is controversial

30
Sleep Across the Human Life Span
31
SIDS
Sleep

• Occurs when an infant stops breathing and
  suddenly dies without an apparent cause.
• American Academy of Pediatrics recommends putting
  infants to sleep on their backs to reduce the
  risk of SIDS.
• Other risk factors low birth weight,
  second-hand smoke, low SES, siblings who died of
  SIDS

32
Sleep in Early Childhood
Sleep

• Most young children sleep through the night and
  have one daytime nap
• Nightmares
• Night Terrors

33
Sleep in Adolescence
Sleep

• Many adolescents are not getting enough sleep
• Try to make up sleep debt on weekends
• Biological clocks shift
• Melatonin production about an hour later each day
  delays sleepiness at night
• Some school districts delay class times to
  accommodate this shift

34
Adulthood, Aging and Sleep
Sleep

• Many adults dont get enough sleep
• Middle age may bring sleep problems
• Wakeful periods at night, less deep sleep
• Many older adults go to bed earlier at night and
  wake up earlier in the morning
• Insomnia increases in late adulthood

35
Life Expectancy and Life Span
Longevity

• Life spanupper boundary of life, maximum number
  of years an individual can live
• Life expectancynumber of years that average
  person born in a particular year will probably
  live

36
The Young-Old, the Old-Old, and the Oldest-Old
Longevity

• Young-old (65 to 74 years)
• Old-old (75 years and older)
• Oldest old (85 and over)
• Many experts on aging prefer to talk about such
  categories in terms of function, rather than age

37
Biological Theories of Aging
Longevity
Cellular ClockTheory
Maximum times that human cells can divide is
about 75 to 80
People age because their cells metabolism
produces unstable oxygen molecules (free radicals)
Free-Radical Theory
MitochondrialTheory
Aging caused by decay of mitochondria
Aging in bodys hormonal system can lower
resistance to stress and increase likelihood of
disease
Hormonal Stress Theory