Chapter 2: Theories of Aging PDF

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Course textbook for the year 2021-2020. Lectures follow closely with the notes from the textbook & quizzes are based on these readings...

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[Theories of Aging] • No theory has been accepted as an adequate explanation of the complex aging process • Available research based on subhuman species and generalizations to humans are questionable • All current research require further research verification • Biological aging range from o Genetic influences o Changes at the cellular level o Consideration of entire organ system changes • Biological aging o Stochastic theories o Nonstochastic theories [Stochastic Theories] • Stochastic theories - view aging as caused by a series of adverse changes in the cells that lead to replicative errors o Randomly and accumulate over time • The four theories of this type include: o Wear and tear theory o Error theory o Cross linking/connective tissue theory o Free radical theory [Wear and Tear Theory] • Earlier attempts to explain biological aging changes • Based on the assumption that continued use leads to worn out or defective parts of the body o Further affected by the accumulation over time of by-products detrimental to cells and tissues normal functioning • Ignores various repair mechanisms available in the body o Muscles need continued use to increase strength and improved functioning [Error Theory] • Cumulative mistakes that occur in DNA and RNA with age o Random errors occur in the 'copying' functions of RNA, impairing cell functions • Aging and death are presumed to be the results of these errors o Transmitted at the cellular level o Research not enough for support tho [Cross-linking or Connective Tissue Theory] • Elastin and collagen - connective tissue proteins that support and connect body organs and structures o Collagen most variable & widespread of all body tissue • Change with age from molecules that are loosely associated with each other - more flexible o To more closely associated with each other - less flexible and more rigid • Cross-linked

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Cross-linking lessens flexibility and also affects accessibility of WBC to fight infection o Decreases access to nutrition o Inhibits cell growth o Reduces ability to eliminate toxins that are by-products of metabolism Research is continuing, but how to prevent it have yet to be clarified

[Free Radical Theory] • Chemical by-product of normal cell metabolism involving oxygen o Also produced by ozone, pesticides, radiation, possibly gasoline , and BP of plastic production • Extremely unstable and last for a second or less o Highly reactive chemically with other substances • Unsaturated fats • Usually destroyed by protective enzyme systems or antioxidants o Some escape and accumulate • Damaging cell membranes, altering normal cell activity, causing death of cells o Vitamins E and C are naturally occurring antioxidants in the body • Research focused on this + other vitamins and dietary supplements o Melatonin, coenzyme Q10, niacin, and food additives butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) • Investigated for possible antioxidant roles [Non-stochastic Theories] • Nonstochastic theories - view aging as caused by replicated errors in cells that are intrinsic and predetermined or programmed o Programmed aging theory o Immunological or immunity theory [Programmed Aging Theory] • Hayflick and Moorehead 1961 raised possibility that a biologic/genetic clock may determine the aging process • Human fetal fibroblastic cells (connective tissue cells) were able to divide ~50 times before deteriorating o Form of programmed aging at the cellular level • LE is thought to be preprogrammed in a species-specific range [Immunological Theory or Immunity Theory] • Composed of series of responses by the body to protect itself against invasion of foreign materials, viruses and bacteria o Bone marrow, spleen, thymus gland, and lymph nodes are major organs of the immune system • Thymus gland decreases in size with age & immune function declines with age o Research has been directed to understanding the significance and implications of thymic developmental changes o Max size in late childhood/early adolescence • Begins to shrink in the teens • Only remnants of thymus remains during middle age

Old age, probably still functioning but amt of tissue is quite small Antigens - materials that initiate an immune response o Body responds by producing antibodies (complex proteins) o Combine with antigens to destroy the invading material Immunosenescence - when the immune system becomes less effective in warding off invading substances o Loses ability to distinguish bt own tissue and invading materials & begins to attack/destroy own tissue • Autoimmune response o T/B lymphocytes decline in function with age Older adults often have decreased immune response, evidenced by o Decreased resistance to disease o Decreased ability to initiate the immune response o More autoimmune disorders A number of diseases common in later life may reflect impaired immune function o Alzheimer's, rheumatoid, atherosclerosis, hypertension, & thromboembolism Role of DNA in the aging process and specific role of genetics in an individual's aging process o Role of telomers in determining the process of aging • "biological clocks" for cell division o Abnormal cell production - an enzyme, telomerase, is produced that adds telomere sequences to the ends of chromosomes at each cell division • Cancer cells Two other theories of biological aging are the neuroendocrine control (pacemaker) theory and the caloric restriction theory o NCT - suggests that aging is due to a programmed decline in nervous, immune, and endocrine system functioning • Hormones under investigation include; ▪ Dehydroeplandrosterone (DHEA) - by adrenal glands ▪ Melatonin - by pineal gland • Both decline with age • Others include ▪ Estrogen, testosterone, growth hormone o CRT - based on earlier research indicating that caloric restriction in diet increases life span, slows metabolism, and at least delays the onset of # of age related diseases Final theoretical view of aging is the apoptosis theory o AT - studies cell death as a noninflammatory gene-driven process occurring normally in the body • Regulated properly = beneficial to body • Dysregulation may cause aging •

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[Psychosocial Theories of Aging] • Considering the ways in which the experiences of earlier years contribute to behaviour later on in life o Even with lack of empirical data for these views a few attempts have been made to devise a series of developmental tasks • Theories based on the assumption that specific tasks are expected to be encountered and eared at certain points/stages in the life cycle o Failure to master tasks at the proper time can interfere with personal-social adaptations • Even with lack of support it does provide guidelines to society's expectations for individual behaviour at different ages o May be useful in working effectively with older adults [Maslow's Hierarchy of Basic Human Needs] - 1968 • As needs of one level are met, individual focuses on the needs of the next level i. Physiological or survival needs ii. Safety and security needs iii. Belonging or affiliation iv. Self-esteem/self-worth v. Need for self-actualization • Important to address each individual according to what their personal needs are the most pressing at the moment to facilitate growth and development [Erikson's Stage Theory of Development] - 1963 • Proposed series of developmental crises that individuals resolves in either a predominately positive/negative direction • Consider middle age and old age stages here Middle Age Generativity vs Desire to leave legacy or leave some tangible 40-65 Ego Stagnation evidence of life lived • Interests and concerns broaden to include social issues and succeeding generations rather than the self • Failure to resolve earlier psychosocial demands may result in increasing preoccupation with self and rigid adherence to the familiar Late adulthood 65-death

Ego Integrity vs To review ones life. Did I do well? How did I Despair do? • Being content with self achieves EI

[Peck's Tasks of Middle and Old Age] - 1968 • Took the last to stages of Erikson's theory and split it into 7 tasks o Four middle age and 3 old age o Sequence was not necessary Valuing Wisdom vs. Physical Powers

Strength & endurance decreases with age • Need to shift value system to gain satisfaction • Mental or intellectual abilities

Socializing vs. sexualizing

Broadening the criteria for meaningful relationships to include other personal qualities

Cathetic (emotional) Flexibility vs. Cathetic Impoverishment

Ability to reinvest emotional energies in new relationships and new roles • May find self isolated if not done as change is a prime ingredient in life

Mental Flexibility vs. Mental Rigidity

Important to remain mentally/intellectually flexible in order to cope and adapt effectively

Ego Differentiation vs. Work Role Preoccupation

Older adults to cling to previous lifestyles as measures of self-esteem find criteria inadequate if they are removed from such roles • OA who value self can enhance their SE though continuing positive interactions w/ others

Body Transcendence vs Body Preoccupation

Those able to rise above their health/physical changes are better able to maintain interest/personal satisfaction from life later on • Others become obsessed with evidence of poor health/PC

Ego Transcendence vs. Ego Preoccupation

See beyond self and maintain active interest in society/people more likely to see self/lives in positive perspective

[Other Developmental Views] • Adolescence - significant age period in our culture o Transition from child to adult generally occurs during this stage • No clear definition/universally accepted guidelines for determining when transition is complete o Uncertainty increases the possibility of conflict • Many important life decisions are made at this time o Career choice, education, marriage, parenthood, establishment of an independent lifestyle, personal identity • Establish firm sense of personal identity/independence becomes most important Early adult • Experimental stage • Decision vs reality years • Testing self against realities of work, home, civic, religious, recreational involvement, and interpersonal relationships Middle age

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Older age

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Consolidation stage Revaluation of self and life Need to start setting priorities for later life • Coping with physical and psychological implications of impending old age o Menopause Some experience depression because of the # of psychologically important events occurring during this time Can be highly satisfying period of life • New interests, intensify current interests, set new priorities Evaluating one's life Life review • Purposeful, constructive effort to review ones life and put it into perspective • Cope wth cumulating losses that usually occurs with advancing age Personal integrity and comfort of believing that life was well lived/generally satisfying are important achievements during this period...