Transcript SR6e Chapter 5

CHAPTER 5
THE PHYSICAL SELF
Learning Objectives
• How do the workings of the endocrine and
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nervous systems contribute to growth and
development across the life span?
To what extent are cells responsive to the
effects of experience?
The Physical Self
• Genetic and environmental forces, e.g. height
– Average: Female 5’4”, male 5’9”
– Can be affected by malnutrition
– Catch-up growth possible
• After illness or periods of malnutrition
– More short people in cold climates
• Smaller body surface for heat loss
The Endocrine System
• Glands that secrete hormones
• Pituitary gland: The master gland
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– Controls all other glands
– Is controlled by the hypothalamus
– Produces growth hormone
Testes secrete androgens like testosterone
Ovaries secrete estrogen and progesterone
The Nervous System
• Brain Development
– Largest, most developed part at birth
– Weight compared to adult brain
• 25% at birth
• 75% at age 2
• 90% at age 5
– Normal experience, stimulation, result in
normal brain
Video: Structure of the Neuron
PLAY VIDEO
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Parts of a neuron. (a) Although neurons differ in size and function, they all contain three main parts:
the dendrites, which receive messages from adjacent neurons; the cell body; and the axon, which
sends messages across the synapse to other neurons. (b) The formation of dendrites leading to
new connections among existing neurons, as well as the myelination of neural pathways, accounts
for much of the increase in brain weight during a baby’s first two years.
Plasticity
• Responsiveness to experiences
– Can be negative
• Vulnerable to damage
• Environmental deprivation
– Can be positive
• Aids in recovery from injury
• Can compensate for each other
• Can benefit from stimulation
• Allows for adaptability
Learning Objectives
• What is lateralization? How does it affect
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behavior
How does the brain change with aging?
What principles underlie growth?
What are examples of each principle?
How can we apply a life-span developmental
approach to our understanding of health?
Brain Development
• Critical period: Late prenatal & early infancy
• Lateralization (at birth)
– Left hemisphere
• Analytic reasoning, language
– Right hemisphere
• Understanding spatial information
• Visual-motor information
– Corpus callosum connects the two
Brain Development 2
• Never truly complete
– Changes occur across lifespan
• Growth spurts in infancy, childhood<,> and
adolescence
• Full adult weight by about age 16
• Processing speed increases in adolescence
• Myelination continues into early adulthood
Brain Development 3
• The Aging Brain
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– Gradual and mild degeneration
Elderly adults
– 5-30% fewer neurons than younger adult
– Greater loss in sensory-motor areas
– Plasticity still possible
Main result of age is slower processing
Principles of Growth
• Procession of growth is orderly
– Cephalocaudal: From head, downward
– Proximodistal: From the center, outwards
– Orthogenic: From global, undifferentiated
to specialized
A Life-Span Developmental Model of Health
• Health: A life-long process
• Determined by both genetic and
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environmental factors
Is multi-dimensional: well-being, illness
Changes involve both gains and losses
Sociohistorical context: SES
Learning Objectives
• What is the difference between survival and
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primitive reflexes?
What are examples of each type of reflex?
What other capabilities do newborns have?
How do locomotion and manipulation of
objects evolve during infancy?
What factors influence the development of
infant’s’ motor skills?
What health issues should be considered
during the first two years of life?
The Infant
• Typically 7 to 7½ lbs., 20 inches long
• Period of rapid growth
• Neonatal reflexes
– Survival reflexes: Clearly adaptive
• Breathing, eye-blink, sucking/rooting
– Primitive reflexes: Less adaptive
• Typically disappear by 4 months
• Babinski: Toes fan, grasping
– Used diagnostically
The Infant 2
• Behavioral States
– Short sleep-wake cycles at first
– Establish more regularity at 3-6 months
– REM sleep
• 50% of the time for newborns
• 25-30% by 6 months
– May be useful for reducing stimulation
– Individuality in infant patterns
The Infant 3
• Strengths and weaknesses
– Sensory system intact
– Ability to learn from experience and from
consequences
– Limited in capacity to move voluntarily
– Intentionality also limited
– Cannot interpret complex stimuli
Infant Physical Behavior
• Developmental norms (see Table 5.4)
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– Average age of mastery
Gross before fine motor skills
Crawling at 7–10 months
Walking at about 1 year
Study of “walkers” (Siegel & Burton, 1999)
– Infants not using walkers sat up, crawled,
and walked earlier
– Need sensory feedback to see feet
Physical Behavior 2
• Manipulating Objects
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– Grasping reflex disappears: 2-4 mo
– Pincer grasp by 6 months
Motor Skills
– Rhythmic Stereotypies
• Rocking, bouncing, mouthing objects,
banging arms and legs
• Precede a skill then disappear
Dynamic Systems Theory
• Rhythmic stereotypes before skill emerges
• A Self-Organizing Process
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– Trying new movements
– Use sensory feedback
A Nature/Nurture Position
– Motor milestones are learned
– Also require maturation
Learning Objective
• How are children’s motor skills advanced
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relative to those of infants?
What factors influence children’s health?
How can health be optimized during
childhood?
The Child
• Age 2 until puberty
– 2-3 inches in height, 5-6 lbs weight
– Bones grow and harden
– Run faster, jump higher, and throw a ball
farther
– Skills very responsive to practice
– Hand-eye coordination, fine motor, and
reaction time all improve
Health and Wellness in Childhood
• Education level of parents a factor
• Nutrition: Well-balanced diet important
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– High-carb foods detrimental
Injuries, auto crashes: Leading cause of
death
Exercise: Promotes physical, cognitive, social
well-being, academic skill
Child obesity: Junk-food, TV
Learning Objective
• What physical changes occur during
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adolescence?
What factors contribute to sexual maturity of
males and females?
What psychological reactions accompany
variations in growth spurt and the timing of
puberty?
Adolescence
• Growth spurt triggered by hormones
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– Peak in height: Age 12/girls, 14/boys
Menarche: Average age 12½
• Earlier in countries with good nutrition
• Maturation different by ethnicity
• AA and MA girls earlier than White
Semenarche: Average age 13
• Emission of seminal fluid
Rates of Development
• Genes set the process in motion
• Hormones responsible for changes
• Environment also important
– Secular trend: Better nutrition
• Earlier maturation, larger body size
– Poorly nourished mature later
– Heavy and tall mature earlier
– Regular strenuous exercise mature later
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Sequence of Events in the Sexual Maturation of Males and females.
Psychological Implications
• Girls become concerned w/appearance
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– Individual reactions vary widely
– Negative views about menstruation
Boys likely to welcome the changes
Family relations remain important
– Distance and conflict with parents
• Usually about only minor issues
Early versus Late Development
• Early males: Advantageous
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– More positive reactions from others
Late/males: Disadvantageous
– More behavior and adjustment problems
Early/females: Disadvantageous
– Subject of ridicule, lower self esteem
– Older peer group = problems
Late/ females: Academic advantages
Differences tend to fade with time
Physical Behavior
• Dramatic physical growth overall
• Boys continue to improve
• Girls tend to level off or decline
– Not totally explained by biology
• Gender role socialization important
• Gender performance gap has narrowed
• E.g., track, swimming, cycling records
Health and Wellness in Adolescence
• Obesity a continuing problem
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– Higher risk: Diabetes, heart, BP problems
– Poor eating habits, sedentary lifestyle
Leading causes of death
– Motor vehicles and violence
Alcohol and drug use, cigarette smoking
– Also result in risky choices
Learning Objectives
• What physical changes occur during
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adulthood?
What are the psychological implications of the
physical changes that occur with aging?
What health concerns arise as adults age?
How can health of older adults be preserved?
The Adult
• Minor changes in the 20s & 30s
• Noticeable by the 40s
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– Wrinkles, gray hair, weight gain
In the 60s: Weight, muscle, bone loss
– Osteoporosis in older women
• Fair, light frame, smokers
• Calcium, exercise, (HRT?)
– Osteoarthritis: Joint deterioration
Functioning and Health
• Most systems show decline with age
– Heart and lung capacity
– Temperature control
– Immune system and strength
– Reserve capacity
• On average, older people are less fit than
younger BUT not all
• Physically active remain fit
The Reproductive System
• Beginning in adolescence
– Sex hormones influence behavior
• Male testosterone
–Levels fluctuate daily
• Female estrogen & progesterone
–Monthly cycle
–PMS? Expectations vs. hormones
–Calcium & Vitamin D helpful
Menopause and Andropause
• Menopause: Estrogen production declines
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– Age range 45-54
– Symptoms: hot flashes, vaginal dryness
– Little anxiety, irritability, depression, or
other stereotypes
– Exercise and adequate sleep helpful
Andropause: Decreasing testosterone
– Symptoms: Libido, fatigue, erection, and
memory problems
Slowing Down
• Balance difficulty affects the ability to walk,
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stand, sit, and turn
Older people with strong muscles and good
cardiovascular capacity can walk briskly
Major change is slowing of the CNS
– Increased RT
– Novel/complex tasks more difficult
Physically-fit older people have quicker RT
Disease, Disuse, or Abuse?
• Birren (1963) study of men aged 65-91
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– Healthy older same as younger
– Conclusion: Aging itself has little effect on
physical and psychological functioning
Disuse: “Use it or loose it!”
– Includes mental exercise
Abuse contributes to decline
– Alcohol, high-fat diet, smoking
Health and Wellness in Old Age
• Acute illnesses less common
• Chronic disease more common
• Most 70-yr-olds: At least 1 chronic impairment
• Tremendous variability
• Exercise, nutrition: Lifelong benefits
– Improves cardio, respiratory functioning
– Slows bone loss, strengthens muscles
– Less depression, delays disability
Diseases Common in Old Age
• Osteoporosis: Smokers, light frame, at risk
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– Increase calcium
– Weight-bearing exercise
Osteoarthritis: deterioration of cartilage
Successful aging
– Both physical and mental functioning
– Positive attitude