Theories Of Aging Flashcards
Hayflick limit theory
Programmed aging
Limit to number of cell replications in life of human cell (50), after which is followed by senescence and death
Children with progeria show lower Hayflick limits
Programmed cell death
Apoptosis
Telomeres (end of chromosomes) continue to shorten c replications until they are gone
*could be considered a replication clock to time cell death
Apoptosis and cell damage
Can be protective and indirectly cause aging
Longevity Assurance Genes
Chromosome 4
May code for proteins that reduce cancer incidence
Sochastic changes
Randomly occurring events related to the environment that cause insult to the body
Non-gen research on aging theories
Cross linkage
Free radicals
Immune system
Neuroendocrine system
Cross linkage
Proteins attaching to large molecules
2 DNA strands cannot be separated normally
With aging, decreased ability to repair cross-links and leads to cell death
Examples - cataracts, renal disease
Free radicals
Highly charged ions with an unpaired e-
Damage cell membranes bc of their affinity for lipids
Have a role in neurotic plaque formation (Alzheimer’s)
Anti-oxidant production decreases c age
Can lead to… Heart disease, stroke, Alzheimer’s
Immune system
Thymus and bone marrow less effective in producing immunity
Therefore, increased rates of infection, auto-immune disease, and cancer c aging
Neuroendocrine
Body tissues become less responsive to endocrine hormones especially of the HPA system, which controls body growth, reproduction, and metabolism
“Body less responsive to system”
Genetic v non-genetic
Biophysical
Gen - cellular aging, pre-programmed, purposeful
Non-gen - related to environment outside of the nucleus, may be internal, external, or environmental sources of damage
Aging genetically controlled, but subject to environmental influence
