1. Physical Development and Biological Aging
Body Growth and Change
The Brain
Sleep
Longevity

2. Patterns of Growth Cephalocaudal pattern: Proximodistal pattern:
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. Height and Weight in Infancy and Childhood
Body Growth and Change
Height and Weight in Infancy and Childhood
Infancy
Average 20 inches, 7 ½ lbs at birth
Triple weight by 1 year
½ adult height, 20% adult weight by age 2
Early
Childhood
Growth slows, patterns vary individually
Girls slightly smaller and lighter
Girls gain fat, boys gain muscle
Middle and Late Childhood
Slower, consistent growth
Muscle mass and strength increase
Boys stronger, body proportions change

4. Changes in Proportions of the Human Body During Growth
Body Growth and Change
Changes in Proportions of the Human Body During Growth

5. Body Growth and Change
Puberty
Period of rapid physical maturation involving hormonal and bodily changes that take place in early adolescence.
Two phases:
Adrenarche-changes in adrenal glands
Gonardarche
Menarche
Spermarche

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

7. Body Growth and Change
Pubertal Growth Spurt

8. Normal Range and Average Development of Sexual Characteristics in Males and Females

9. Secular Trends in Puberty
Body Growth and Change
Secular Trends in Puberty
Onset of puberty beginning earlier:
Norway — menarche at 17 in 1840s, now 13
U.S. — menarche at 15 in 1840s, now 12½
White girls at average age of 10
African American girls at average age 8 to 9

10. Body Image in Puberty Adolescents become preoccupied by bodies:
Body Growth and Change
Body Image in Puberty
Adolescents become preoccupied by bodies:
Overall, girls less satisfied, boys more satisfied
Throughout puberty:
Girls’ dissatisfaction increases-
body fat increases
Boys’ satisfaction increases-
muscle mass increases

11. Body Image in Puberty Early and Late Maturation:
Body Growth and Change
Body Image in Puberty
Early and Late Maturation:
Early boys more positive, better peer relations.
Late boys less positive but have more positive identity by 30s than early boys.

12. Body Image in Puberty Early and Late Maturation:
Body Growth and Change
Body Image in Puberty
Early and Late Maturation:
Early girls more at risk for problems
Smoking and drinking.
Depression and eating disorders.
Lower education and occupational
attainment.
Early dating and sexual experiences.
Mental disorders and behavior problems.

13. Middle Adulthood Physical: Lose height, gain weight.
Body Growth and Change
Middle Adulthood
Physical:
Lose height, gain weight.
More skin wrinkling, sagging in 40s and 50s.
Youth-oriented culture motivates life style changes.
Strength, bone density, flexibility decrease:
1 to 2 percent loss each year after age 50.
Sarcopenia: age-related loss of muscle mass.

14. Middle Adulthood Cardiovascular system and lungs:
Body Growth and Change
Middle Adulthood
Cardiovascular system and lungs:
HDL and LDL cholesterol, clogged arteries.
Hypertension: blood pressure increases.
Decreased lung capacity after age 55.
Sexuality changes:
Climacteric: Fertility declines.
Menopause: Menstrual periods cease.

15. Lung Capacity, Smoking and Age
Body Growth and Change
Lung Capacity, Smoking and Age

16. Late Adulthood Variability in physical declines:
Body Growth and Change
Late Adulthood
Variability in physical declines:
Socioeconomic status is a big factor.
Physical appearance:
Wrinkles, age spots, height and weight loss
Weightlifting can slow process.
Circulatory system:
Increased blood pressure; linked to chronic
conditions and longevity.

17. The Brain In Infancy Changing neurons:
Rapid growth of myelin sheath, dendrite and synapse connections.
Blooming and pruning of connections in brain.
Peak synaptic overproduction influenced by heredity and environment.

18. The Brain
Dendritic Spreading

19. The Brain In Infancy At birth, greater activity in left hemisphere
specializes as infants listen to speech.
Motor control begins about 2 months.
Brain areas do not mature uniformly.
Extensive brain development in utero:
Born with about 100 billion neurons.
Enriched early experiences can enhance
brain growth and functioning.

20. The Brain
The Brain In Infancy
Shaken Baby Syndrome

21. Synaptic Density in Human Brain from Infancy to Adulthood

22. The Brain in Childhood During early childhood, the brain and head
grow more rapidly than any other part of the
body.
Greatest anatomical brain increases from
ages 3 to 15 years.

23. Growth Curves for Head and Brain and for Height and Weight
The Brain
Growth Curves for Head and Brain and for Height and Weight

24. The Brain in Adolescence
Growth still occurs in adolescence:
Corpus Callosum thickens.
Prefrontal cortex grows: reasoning, self-control, and decision making.
Amygdala matures early: emotions and anger.
Adolescent emotions:
Slow development of prefrontal cortex.
Poor self-control; seek rewards and pleasure.
Seek novelty; increased risk-taking.
Lack of practical experiences; immature judgment.

25. Adulthood and Aging The Shrinking-Slowing Brain:
The Brain
Adulthood and Aging
The Shrinking-Slowing Brain:
Brain loss: 5-10% of weight in ages 20 to 90
Dendrites decrease.
Death of brain cells
Shrinkage of prefrontal cortex.
General slowing of function in brain and spinal cord begins in middle adulthood and accelerates in late adulthood.
Reductions in neurotransmitters.

26. The Adapting Brain Grows new brain cells throughout life
The Brain
The Adapting Brain
Grows new brain cells throughout life
depending on environment.
Dendrite growth continues in adults.
Brain rewires to compensate for losses.
Less lateralization with age.
Findings from Nun Study:

27. Sleep in Infancy Newborns average 16-17 hours a day.
Varied sleeping patterns-
Longest sleep period: 11 pm to 7 am.
May change from longer to shorter sleep periods.
Most close to adult patterns by 4 months.
More REM sleep than any other time of life.
Shared sleeping with parents is controversial.

28. Sleep Across the Human Life Span

29. Sleep
SIDS
Infant stops breathing, usually during night, and suddenly dies without apparent cause.
Having siblings who died of SIDS.
African American and Eskimo infants.
Lower SES groups.
Passive exposure to cigarette smoke.
Infants ages 4 to 6 wks
Sleeping on stomachs, use of soft bedding
Low birth weight; diagnosed with sleep apnea
Sleeping with pacifier

30. Sleep in Early Childhood
Most young children sleep through the night and have one daytime nap.
Nightmares: Frightening dreams are more common.
Night Terrors: Sudden arousal from sleep.

31. Sleep in Adolescence Many adolescents are not getting enough sleep:
Average 9½ hours when available
Like to stay up late, sleep late in mornings
Biological clocks have hormonal shift
Melatonin production — about an hour later each day delays sleepiness at night.

32. Sleep in Adolescence Sleep deprivation and school performance:
Grogginess and inattentiveness
Poor test performance
Discipline problems
Reports of illness and depression
Low self-esteem
Ineffective stress management, exercise, diet

33. Adulthood and Aging 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.
Afternoon naps .
Insomnia increases in late adulthood.

34. Life Expectancy and Life Span
Longevity
Life Expectancy and Life Span
Life span:
Upper boundary of life, maximum number of years an individual can live.
120 years of age.
Life expectancy:
Number of years that an average person born in a particular year will probably live.

35. Life Expectancy Females average 80 years, 74 years for males.
Longevity
Life Expectancy
Females average 80 years, 74 years for males.
Gender differences influenced by biological factors – extra X for females.
Life expectancy varies across countries.
U.S. men more likely to die from leading causes of death.
Associated with lifestyle and workplace stress.

36. Centenarians Numbers increasing: Genes, heredity, and family history
Longevity
Centenarians
Numbers increasing:
Genes, heredity, and family history
Women who have never married
Ability to cope successfully with stress
Education, health, and lifestyle
Individual personality
Highest ratio in Okinawa.

37. Biological Theories of Aging
Longevity
Biological Theories of Aging
Cellular Clock Theory
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
Mitochondrial Theory
Aging caused by decay of mitochondria; oxidative damage
Aging in body’s hormonal system can lower resistance to stress and increase likelihood of disease
Hormonal Stress Theory