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23 Cards in this Set
- Front
- Back
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What are two similarities between normal aging in the brain and disease-related deficits?
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*both take time to develop
*both involve age-dependent histological changes in the brain |
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Give two examples of histological changes that are characteristic of neurodegenerative diseases but are also seen in unaffected individuals.
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*amyloid plaques as seen in AD
*neurofibrillary tangles as seen in AD *Lewy bodies as seen in PD |
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What is the key structural feature of aging in the brain?
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Atrophy
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What are the two main components of atrophy in the brain? At what age does this process begin?
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*shrinkage of tissue and ventricular enlargement
*usually begins immediately after maturation, at age 18-20 |
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T/F:
Age-related atrophy of the brain is usually limited to the temporal lobes. |
False: the atrophy seen in normal aging is global.
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How are exercise and brain atrophy related?
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Some experiments have shown decreased atrophy in individuals who exercise regularly.
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Which tissue is more prone to atrophy - gray or white matter? How is this manifested clinically?
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White matter is more prone than gray matter to atrophy. Yhis results in demyelination, as evidenced by a loss of conduction velocity in older persons.
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How does age-related atrophy affect neuronal structure?
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There is a loss of dendrite arborization and shrinkage of the cell body.
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Which of the special senses seems to be most vulnerable to age-related functional loss?
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Olfaction, followed by presbyopia and presbyacusis (vision and audition).
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T/F:
There is a large difference in age-related functional deficits in gait and balance between "old-old" and "young-old" persons, but not in the special senses. |
False: there is a large difference in functional deficits in all of these areas between old-old and young-old persons.
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List the three basic mechanisms that have been postulated to cause age-related atrophy in the CNS.
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1.Compromised blood flow
2.Oxygen free radicals 3.Deprivation of trophic factors |
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What two trophic factors seem to be involved in age-related loss of brain mass? What evidence supports this idea?
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IGF-1 and GH, because they are integral to the increase in brain mass seen in development and have been shown to decline beginning at age 20.
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What structure has been postulated to be a timing device for the onset of age-related CNS atrophy?
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Hypothalamus.
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How are metabolic rate and lifespan related? What is the reason for this relationship?
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They are inversely related. It has been postulated that faster metabolism leads to greater production of oxygen free radicals which damage tissue and accelerate the aging process.
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What types of cells are most susceptible to damage by oxygen free radicals?
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Post-mitotic cells, such as neurons or muscle cells.
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What role have oxygen free radicals been postulated to play in the aging process?
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These compounds are known to cause tissue damage and it is thought that their accumulation over time is related to the overall decline seen in aging. In vitro they have been shown to cause atrophy and cell loss.
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T/F:
Most of the decrease in brain mass seen in aging is due to loss of neurons in the cerebral cortex. |
False: most of the decrease in brain mass is due to global atrophy rather than cell loss.
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What relationship has been demonstrated between caloric intake and lifespan in experimental animals?
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An inverse relationship, with a drastically reduced intake being associated with increased lifespan.
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How have the genes of drosphila been experimentally altered such that they have a longer lifespan?
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Species that have been engineered to overexpress anti-oxidants have shown longer lifespans.
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What piece of evidence has been taken to show that acclerated aging is NOT the cause of neurodegenerative disease?
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Patients with Werner's syndrome (which causes accelerated aging) do not have a higher incidence of AD or other similar diseases.
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What correlation was revealed in the Nun Study?
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There seemed to be a direct relationship with grammatical ability in early life and incidence of AD.
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What is the usual speed of age-related decline in functioning?
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It is marked by slow decline rather than rapid loss.
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How is iron accumulation associated with age-related atrophy?
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Iron catalyzes to production of oxygen free radicals and has been shown to accumulate with age in areas of the CNS.
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