What is old? Flashcards
other word for ageing
senescence
influences of rate of ageing 3
nutrition
lifestyle
environment
cause of ageing
multiple mechanisms –> subtle molecular and cellular faults (begins in uter) and multiple repair mechanisms
what is the genetic contribution to ageing
the genetic setting of repair settings
4 parts of theory of ageing
IPDU
- intrinsic
- progressive
- deleterious
- universal to the species
factors that affect ageing at a cellular level
Degenerating Cells Make Stoners Old
- DNA (short telomeres, loss of gene function)
- Calorie intake (more –> more ageing)
- Mitochondria degeneration
- Sirtuins (enzymes, longevity pathways)
- Oxidative stress
damage to DNA that contributes to ageing
- shortened telomeres
- loss of gene function
explain wear and tear theory of ageing
chance environmental damage accumulates over time , inability to repair this damage
probably explains SOME of ageing
explain mis-repair theory of ageing
cells repair serious repeated damage in order to survive to reproductive age
more errors with age –> tissue disorganisation
explain oxidative stress
imbalance between reactive oxygen species ROS and cell’s ability to detoxify these to prevent damage
ROS disrupt normal signalling process
what activates cellular stress proteins4
HUTT
- heat
- UV light
- trace metals
- toxins eg hsp60, 70,90
which theory says ageing is the price to pay for survival
mis-repair theory
effect on cells of free radicals
alter molecular structure and function –> cell dysfunction, cancer etc
sources of free radicals
normal metabolism
air/ food
radiation
what prevents free radical damage and how
anti-oxidants eg provitamin A, vit c,E
donate electrons to free radicals
(but no experiments with diet)
how do sirtuins decrease ageing
regulation of SAT
stress
apoptosis
transcription
what is a telomere and function
end part of chromosome, 2000 repeats of TTAGGG
non-coding DNA that stops ends of chromosomes sticking together
explain molecular senescence/ molecular clock
partial loss of telomeres with each round of cell division
telomerase function
cell immortality
can telomeres increase in length
poss yes, with healthy lifestyle
what % is lifespan genetically determined
25%
2 ageing things influenced by genetics
- repair mechanisms
- basal metaboli rate
relationship between basal metabolic rate and ageing
BMR slows with age –> increases longevity
how does the immune change with ageing
decreases (mainly T cells)
BUT increased autoimmunity
3 autoimmune disorders ass with ageing
- arthritis
- glomerular nephritis
- hypo/hyperthyroidism
what is likely to cause age-related brain changes 6
6
- decreased connectivity/ neurotransmitter function
- reduced brain plasticity via biochemical changes
- neurone loss with proliferation of glia
- decrease brain mass (MRI studies
- increased senile plaques
- inc neurofibrillary tangles
- inc infarcts/ stroke
after what age does mental decay rapidly increase
75yo
what causes loss of smell in elderly
loss of olfactory cells in nasal epithelium
what causes loss of taste in elderly
loss of gustatory receptor cells in taste buds
what else may contribute to loss of smell/ taste
- viral infection
- medications
- radiotherapy
how does this change in elderly:
a. metabolism
b. physical plasticity of tissues
c. organ functional reserve
d. vulnerability to stress/ infection
a. metabolism: decreases (less energy produced)
b. physical plasticity of tissues:declines, due to more collagen cross-links
c. organ functional reserve: decreases
d. vulnerability to stress/ infection: increases
what gives signs of frailty, disability, disease
decreased functional reserve of organs
% of over 65s without teeth
30-40%
critical number of teeth for functional dentition
21
compare life expectancy in british countries
england>wales > NI >scotland
2 diseases ass with periodontal disease
diabetes (bidirectional relationship)
stroke (maybe)
link between oral infection and chest infection
- plaque is resevoir of bacteria to enter lungs
- aspiration (common in nursing homes) caused by substances from mouth entering lungs
function of cellular stress proteins
protein protection/ repair of important proteins damaged by ROS
Degradation of ROS/ proteins
what activates cellular stress proteins 4
HUTT Heat Uv light Trace metals Toxins (hsp 60, 70,90
define oxidative stress
imbalance between reactive oxygen species and the cells ability to detoxify these to prevent damage
effect of oxidative stress
dirsrupts normal signalling processes
