3.2 Ageing -Biological Effects Flashcards
What is one of the reasons why people live to an older age?
Better at preventing deaths in the early and middle years of life - sewerage, housing, clean drinking water etc. Vaccines etc. Antibiotics.
What evidence is there against programmed ageing?
In wild conditions, animals often die before they can start showing signs of ageing, it makes no sense to have a programme for ageing and death if that age is rarely reached in the wild
What is the disposable soma theory?
Period of longevity is assured by maintenance and repair, - its only worth investing energy for maintenance and repair for as long as that animal is expected to live - otherwise energy from other sources would need to be taken - so after a certain age, maintenance and repair reduces
So what causes ageing?
Primarily caused by damage
Longevity is regulated by resistance and repair
Multiple mechanisms involved
Inherently stochastic - influenced by chance
How does cell damage accumulate?
It accumulates from day one
Damage, or mutation, occurs inevitably with each cell division
Mutations increase throughout life
What else is responsible for cell damage?
Reactive oxygen special - free radicals - are formed as by products of energy generation within the mitochondria
They damage multiple targets within the cell, including DNA with cell nucleus and mitochondria.
What effect does mutant mitochondria have?
It impairs the cells ability to make the energy it needs to function
Mutations in the mitochondria accumulate in an accelerating rate throughout life
What are telomeres?
Telomeres protect chromosome ends – they shorten with cell division and this is accelerated by biochemical stress.
How are telomeres linked with ageing?
Prematurely short telomeres are linked with increased risk of age-related disease and diminished survival.
People suffering severe chronic stress (eg carers of those with dementia and other conditions) have shorter telomeres.
Do genes affect ageing?
Twin studies
Genes account for 25% of what determines human longevity - hard to find - multiple ones
How does nutrition affect ageing?
2 unit increase in Meditteraneaness diet, results in 8% reduction of overall mortality
What other factor can affect ageing?
Socioeconomic status
People with a higher socioeconomic status are more likely to have a later age of onset of a limiting long term condition
How can exercise impact ageing?
People who do more exercise have a lower mortality
