1. CHAPTER 5 THE PHYSICAL SELF

2. Learning Objectives How do the workings of the endocrine and nervous systems contribute to growth and development across the life span? To what extent are cells responsive to the effects of experience?

3. 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

4. The Endocrine System Glands that secrete hormones Pituitary gland: The master gland –Controls all other glands –Is controlled by the hypothalamus –Produces growth hormone Testes secrete androgens like testosterone Ovaries secrete estrogen and progesterone

6. 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

7. Video: Structure of the Neuron PLAY VIDEO

8. 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.

9. 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

10. Learning Objectives What is lateralization? How does it affect 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?

11. 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

12. 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

13. Brain Development 3 The Aging Brain –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

14. Principles of Growth Procession of growth is orderly –Cephalocaudal: From head, downward –Proximodistal: From the center, outwards –Orthogenic: From global, undifferentiated to specialized

15. A Life-Span Developmental Model of Health Health: A life-long process Determined by both genetic and environmental factors Is multi-dimensional: well-being, illness Changes involve both gains and losses Sociohistorical context: SES

16. Learning Objectives What is the difference between survival and 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?

17. 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

20. 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

21. 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

22. Infant Physical Behavior Developmental norms (see Table 5.4) –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

23. Physical Behavior 2 Manipulating Objects –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

25. Dynamic Systems Theory Rhythmic stereotypes before skill emerges A Self-Organizing Process –Trying new movements –Use sensory feedback A Nature/Nurture Position –Motor milestones are learned –Also require maturation

26. Learning Objective How are children’s motor skills advanced relative to those of infants? What factors influence children’s health? How can health be optimized during childhood?

27. 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

28. Health and Wellness in Childhood Education level of parents a factor Nutrition: Well-balanced diet important –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

30. Learning Objective What physical changes occur during adolescence? What factors contribute to sexual maturity of males and females? What psychological reactions accompany variations in growth spurt and the timing of puberty?

31. Adolescence Growth spurt triggered by hormones –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

32. 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

33. Sequence of Events in the Sexual Maturation of Males and females.

34. Psychological Implications Girls become concerned w/appearance –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

35. Early versus Late Development Early males: Advantageous –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

36. 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

37. Health and Wellness in Adolescence Obesity a continuing problem –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

38. Learning Objectives What physical changes occur during 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?

39. The Adult Minor changes in the 20s & 30s Noticeable by the 40s –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

40. 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

42. 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

43. Menopause and Andropause Menopause: Estrogen production declines –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

44. Slowing Down Balance difficulty affects the ability to walk, 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

45. Disease, Disuse, or Abuse? Birren (1963) study of men aged 65-91 –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

46. 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

47. Diseases Common in Old Age Osteoporosis: Smokers, light frame, at risk –Increase calcium –Weight-bearing exercise Osteoarthritis: deterioration of cartilage Successful aging –Both physical and mental functioning –Positive attitude