The Ageing Process Flashcards
what is ageing
progressive, generalised impairment of function resulting in a loss of adaptive response to disease
what causes human ageing
random molecular damage during cell replication
what can increase ageing/cellular damage
inactivity
poor diet
inflammation
7 factors contributing to ageing
Mutations in chromosomes Mutations in mitochondria Intracellular aggregates Extracellular aggregates Cellular loss (lack of stem cells/replacement) Cell senescence (useless/harmful cells) Extracellular protein crosslinks
what is a telomere
end part of each chromosome arm
what happens to telomeres in the ageing process
they shorten after every replication, eventually leaving to cell senescence as it is too short to sustain replication
what is the hayflick limit
the limit to ageing - when the telomeres are so short they can no longer divide
most cells dont divide enough times to reach this limit
what does telomerase do
a protein complex active in some cells which need to divide many times - re-extends the shortened telomeres
what damage to macromolecules occurs during ageing
DNA mutations/breaks
Lipid per oxidation
Protein misfolding, aggregation, cross linking
what causes damage to macromolecules in ageing
ionising radiation
reactive oxygen species (diet, radiation, inflammation).
Extrinsic toxins
what 4 main cellular processes are causes by macromolecule damage
Repair
Apoptosis
Senescence
Malignant transformation
what is the antagonistic pleiotrophy theory of ageing
that genes are beneficial in early life but detrimental in late life
act as a ‘time bomb’ in later life contributing to death of the organism from cell senescence
what is frailty
loss of homeostasis and resilience causing increased vulnerability to external stresses
increased risk of falls, delirium, disability and death
what are the 2 models of frailty
deficit accumulation
Phenotypic (fried score)
how does the phenotypic model identify frailty
Unintentional weight loss Low grip strength Self-reported exhaustion Low physical activity levels Slow walking speed
(3 or more = frail)
how does the deficit accumulation model identify frailty
count how many body systems have a deficit - the index is deficits divided by the number of systems
between 0-1 is frail
what difference does frailty make to health
minor illness can have a profound effect in frail people - high risk complications from hospitalisation
true/false - multimorbidities and frailty is the same thing
false
you can have no multimorbidities and be frail or have multimorbidities and be robust
what does physical activity protect against in old age
Heart disease Diabetes Cancers Mild depression Dementia and Alzheimers
what are some medical characteristics of old age
multi-morbidity multiple medications Illness presenting in atypical ways falls, immobility, delirium need for rehabilitation
