Lecture 31 Flashcards
What is sarcopenia?
Age-related muscle wasting
What is cachexia?
A component of sarcopenia, but not the same
Where does sarcopenia occur most in?
Bedridden, slow walking speed, and those with significant atrophy
What are the effects of sarcopenia?
low muscle mass
low muscle strength
low physical performance
Who does sarcopenis occur most in?
sarcopenia doesnt discriminate against almost anyone, everyone will develop it regardless of their background
What is the effect of age on performance?
Gradual decrease, even in those that train
What does sarcopenia look like?
Diminished cross sectional area and infiltrating connective tissue
When is the onset of sarcopenia?
~50 years old
Which is affected more by sarcopenia, fast or slow muscles?
fast, undergo most atrophy
increases type 1 fibre proportion
Name some factors controlling muscle mass as we age
Nutrition Hormones & genetics Innervation Inflammation Oxidative stress Blood flow Exercise Disease Protein synthesis & degredation
What kind of disease is sarcopenia?
neuromuscular syndrome
What is believed to happen in sarcopenia?
Neural supply to fast fibres is lost, resulting in muscle wasting, as well as remodelling many to type 1 fibres
What are the possible causes of sarcopenia?
loss of signals from nerves to muscles
or
loss of signals from muscles to nerves
What is the effect of age on contracting?
impaired release and reuptake of Ca2+, results in slower contraction
What happens in neural connections to muscles with age?
Motor neurons are lost, especially in type 2 fibres
Some neurons can give out branches called sprouts, reinnervating type 2 fibres by a type 1 neuron, converting it to type 1
What changes occur in nerves during sarcopenia?
widened nerve end plates
longer nerve terminals
fewer side branches
motor end plates usually undergo constant remodelling
Is sarcopenia inevitable?
Yes, it will happen to everyone eventually
How can sarcopenia be attenuated?
Strength training, flexibility, balance and aerobic exercise for the elderly to increase their strength and increase hypertrophy
Suggests adaptive capacity remains
Neither reverses sarcopenia damage nor stops it however
Does sarcopenia attenuation reverse damage?
No, has only therapeutic effect
What is the effect of aging on hormones?
Many growth hormone levels decrease, reducing capacity to repair damaged cells
Does growth hormone administration reduce sarcopenia?
No, mostly because they are not coupled with exercise training, little effect on its own
What is the best intervention for sarcopenia?
Reducing the disease burden by increasing strength and physical function over increasing lean mass. They dont need mammoth muscles, just normal adult sized so they can rely on themselves
