Chapter 3 Theories of Aging Flashcards
Biological aging
- “senescence”
- Expression of declining functional capacity of most basic structures in cells, which in turn affects functioning of organism.
- A complex genetically regulated interactive process of change in every living organism
Social age
Measured by age-graded behaviors, carrying expected status and role within a particular culture or society
Programmed theories of aging
- Suggest that aging is the result of predictable cellular death
- Cells and organisms have a genetically predetermined lifespan known as the biological clock.
Neuroendocrine Control or Pacemaker Theory
-Explains aging as a programmed decline in the functioning of the immune, nervous, and endocrine systems.
-“Replicative senescence”: cells lose their ability to reproduce
Adrenal=dehydrpiandrosterone DHEA
Pineal=decreased melatonin
Decreased: growth factor, estrogen and testosterone
Immunity Theory
- Aging is a programmed accumulation of damage and decline in the function of the immune system: “immunossenescence”
- Damage is a result of oxidative stress
- T-cells thought to be responsible for increasing age-related auto-immune disorders
Error Theories
-Aging is the result of an accumulation of random errors in the synthesis of cellular DNA and RNA
Wear and Tear Theory
- Cellular errors a result of “wearing out” over time from continued use
- A progressive decline in cellular function or increased cellular death
- Internal and External stressors: Pollutants and Metabolic by-products (free radicals)
Cross-linkage Theory
- Aging is a product of accumulated damage from errors associated with cross-linked proteins
- Initiated by blood glucose linking with protein in process of glycosylation or glycation: cross-linked proteins (i.e. collagen) become stiff and thick–evidenced by stiffened joints and decreased skin elasticity.
Oxidative Stress Theory (Free Radical Theory)
- Cellular errors are result of random damage from free radicals (unbound/unescorted Fe, Oxygen, etc…)
- Referred to as “oxidative damage”
- Mitochondrial DNA most affected by these changes
- Antioxidants are thought to limit free radical damage: Vitamin C, E, and other Herbal Supplements
“Free radicals are entirely……
…..oxidative stress.”
Telomeres
- Repeated sequences on chromosomes essential for cellular reproduction
- Shorten with every cell cycle
- Hypothesized to be contributory to senescence of the cells
- Enzyme tolomerase counteracts this effect
- Manipulation of telomeres has potential to affect development and treatment of disease and aging itself.
Epigenetics
Science of how genes are influenced by environment, lifestyle, role, genes, gender, and other factors.
Role Theory
- Age norms: Socially and culturally constructed expectations of behavior at times in one’s life and in pre-established roles.
- Popular culture continues to challenge role theory and age norms: Older adults are assuming roles and behaviors unimagined when role theory first proposed.
Activity Theory
- Attempted to predict and explain how individuals adjusted to age-related changes by looking at one’s level of activity and productivity.
- Popular because it is consistent with Western society’s emphasis on work, wealth, and productivity.
- Need to maintain a productive life for it to be a happy one: All focused on increased activity = increased life.
Disengagement Theory
- Withdrawal of elders from their roles and activities earlier in life necessary to allow transfer of power to younger generations.
- Probably provided the basis for age discrimination.
- Challenged both socially and legally.
- This is used to be considered good and necessary (elder participation now considered beneficial to society)
