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WHAT MAKES US AGE?

WHAT MAKES US AGE?. Life Cycle II. JOHN TURNER. AGE 77. AGE 67. ELEANOR HYNDMAN. AGE 80. AGE 90. MOVE IT OR LOSE IT--Can you be ACTIVE & OLD?. WHY DO WE AGE?. IS IT GENETICS? ENVIRONMENTAL DAMAGE?. DEVELOPMENTAL— GENETIC THEORIES

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WHAT MAKES US AGE?

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  1. WHAT MAKES US AGE? Life Cycle II

  2. JOHN TURNER AGE 77 AGE 67

  3. ELEANOR HYNDMAN AGE 80 AGE 90

  4. MOVE IT OR LOSE IT--Can you be ACTIVE & OLD?

  5. WHY DO WE AGE? • IS IT GENETICS? • ENVIRONMENTAL DAMAGE?

  6. DEVELOPMENTAL— GENETIC THEORIES Genetic makeup determines factors directly affecting aging Programmed & directed in the body Aging is Predetermined ENVIRONMENTAL— NON- GENETIC THEORIES Due to random events that occur over time Aging caused by environmental damage Controlled extrinsically THE BIG QUESTION

  7. Theories of Aging • Finite Lifespan • Immune System Failure • Hormonal • Energy/Caloric Restriction • Error Theory • Redundant DNA • Transcription • Cross-Linking

  8. Finite Limit Theory • Hayflick & Moorehead (1961) • Landmark Study--Cells Have Time-clock • Cells Have Limited Life Span • Apoptosis=Programmed cell death • Cells Proliferated and Divided • Alterations & Degeneration • Cessation of Growth & Division

  9. Neuroendocrine & Hormonal Theory • Denckla (1974) Endocrinologist Gerontologist • Aging Mediated in Brain • Functional Decrements in neurons and associated hormones dictates aging rates

  10. Immunological Theory • Walford (1969, 1979) • Reduced T-cell function with age • Decline in Immune System Function • Immune System unable to distinguish between self & non-self • Age associated increase in autoimmune disorders • Lupus, Scleroderma

  11. Free Radical Theory • Accumulates Over Time from Oxygen Metabolism • Charged Ion with unpaired electron • Damages membrane proteins, mitochondria, etc. • Decreased cellular integrity • Free radicals associated with atherosclerosis, cancer

  12. Metabolism, Free Radicals, & Life Span • Metabolic Rate Directly Related to Free Radical Production • Inverse Relationship Between Metabolic Rate & Life Span • Hypothesis--Lower metabolic rate, lower free radical production, increase life span

  13. Caloric Restriction Theory • Walford (1987)--”Dr In Vivo” • Restriction of Caloric Intake • High quality nutrient/low calorie diet increases longevity • Supplements with vitamins/minerals/moderate exercise • Gradually lose weight until maximal metabolic efficiency, retards aging

  14. Error Theory • Orgel (1963) • “Any accident or error in either the machinery or the process of making proteins would cascade into multiple effects” • DNA--RNA--protein synthesis • Accumulation of errors over time • “Error Crisis” result in impaired cell function

  15. Redundant DNA • Medvedev (1972) • Combination of Finite Limit & Error • Ability to repair errors to genetic material decreases with age • Errors in Cellular DNA • Reserve DNA (error free) utilized • Cell death when reserve DNA gone

  16. Cross-Linking Theory • Bjorksten (1942) • Proposed Chemical reaction of Cross Linking of Macromolecules related to aging • Occurred during sun tanning--lose elasticity • Loss of Tissue Elasticity

  17. WHY SO MANY THEORIES? “Number of hypotheses is generally inversely proportional to the clarity of the problem.” --Frolkis

  18. IS THERE A RIGHT ANSWER? • Biologic Gerontology New Field • Can One Single Theory Explain All Aging Processes?

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