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

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

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

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

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

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

Body Growth and Change Pubertal Growth Spurt

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

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

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

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.

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.

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.

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.

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

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.

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.

The Brain Dendritic Spreading

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.

The Brain The Brain In Infancy Shaken Baby Syndrome

Synaptic Density in Human Brain from Infancy to Adulthood

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.

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

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.

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.

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:

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.

Sleep Across the Human Life Span

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

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.

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.

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

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.

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.

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.

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.

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