LIFE-SPAN DEVELOPMENT

1. 3 A Topical Approach to LIFE-SPAN DEVELOPMENT Physical Development and Biological Aging John W. Santrock

2. Body Growth and Change Patterns of Growth • Cephalocaudal pattern—growth occurs first at the top—the head—and gradually proceeds from top to bottom • Proximodistal pattern—growth starts at the center of the body and moves toward the extremities

3. Body Growth and Change Height and Weight in Infancy and Childhood

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

5. Heredity Hormones Androgens Estrogens Weight and Body Fat Environmental influences: secular trend Body Growth and Change Determinants of Puberty

6. Body Growth and Change Hormone Levels by Sex and Pubertal Stage for Testosterone and Estadiol

7. Body Growth and Change Pubertal Growth Spurt

8. Development of Sexual Characteristics - Males

9. Development of Sexual Characteristics - Females

10. Body Growth and Change Body Image in Puberty • 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. Body Growth and Change Early Adulthood • Many reach peak of muscle tone and strength in late teens and twenties • Decline in the thirties

12. Body Growth and Change Middle Adulthood • Lose height, gain weight • Physical appearance concerns in youth-oriented culture • Strength, bone density, flexibility decrease • Cholesterol, blood pressure rise • Sexuality changes • Climacteric—fertility declines • Menopause—woman’s menstrual periods cease

13. Body Growth and Change Late Adulthood • 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. Body Growth and Change Changes in Body Composition with Age

15. The Brain Brain Physiology • Neuron—nerve 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 Brain The Neuron

17. Cerebral Cortex • Cerebral cortex makes up 80% of brain volume and is critical to perception, thinking and language. • Lateralization—specialization of functions in one hemisphere of cerebral cortex

18. The Brain The Human Brain’s Hemispheres

19. The Brain The Brain’s Four Lobes

20. The Brain Functions of Lobes of the Cortex 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 The Brain in Infancy • 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 The Brain in Childhood • During early childhood, the brain and head grow more rapidly than any other part of the body • Some of brain’s increase due to myelination and some due to increase in number and size of dendrites

25. Brain and Body Growth

26. The Brain The Brain in Adolescence • 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 Brain The Shrinking, Slowing 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 Sleep: Infancy • 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. Sleep SIDS • 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 Sleep in Early Childhood • Most young children sleep through the night and have one daytime nap • Nightmares • Night Terrors

33. Sleep Sleep in Adolescence • 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. Sleep Adulthood, Aging and Sleep • Many adults don’t 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. Longevity Life Expectancy and Life Span • Life span—upper boundary of life, maximum number of years an individual can live • Life expectancy—number of years that average person born in a particular year will probably live

36. Longevity The Young-Old, the Old-Old, and the Oldest-Old • 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. Longevity Biological Theories of Aging 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 body’s hormonal system can lower resistance to stress and increase likelihood of disease Hormonal Stress Theory