Skeletal Muscle in Ageing Flashcards
What is sarcopenia
irreversible age-related muscle atrophy
What is the opposite of hypertrophy (structural proteins added to muscle cell)?
Atrophy (loss of structural proteins from skeletal muscle fibres)
why does muscle atrophy occur?
due to disuse
How do we combat muscle atrophy
exercise
In what kind of athlete is sarcopenia more obvious?
athletes whose sports require strength and powerful movements, such as sprinting,
whereas the effects of age are less noticeable in endurance athletes such as marathon runners or long-distance cyclists.
What are possible causes of sarcopenia?
may be caused by a reduction in FG fibers that hydrolyze ATP quickly to produce short, powerful contractions.
There may also be a reduction in the size of motor units, resulting in fewer fibers being stimulated and less muscle tension being produced.
What kind of muscle fibres are more abundant in old people?
Slow oxidative
Can sarcopenia be delayed?
To some extent by exercise, as training adds structural proteins and causes cellular changes that can offset the effects of atrophy.
What does exercise do to muscles?
produce greater numbers of cellular mitochondria
increase capillary density
increase the mass and strength of connective tissue.
In who are the effects of sarcopenia more pronounced?
People who are sedentary
What problems can result due to sarcopenia?
This can lead to a decrease in quality of life and medical problems, such as joint problems because the muscles that stabilize bones and joints are weakened.
Problems with locomotion and balance can also cause various injuries due to falls.
What is muscle atrophy?
the number of sarcomeres and myofibrils disappear (but not the number of muscle fibers).
Around when does decline in muscle mass start?
As early as 25
What factors contribute to muscle aging?
Decreased proliferative ability of muscle cells and the adverse effects of oxidative stress that can cause premature muscle aging.
How might we reverse muscle aging?
Genetically silencing p16INK4a, a regulator of cellular senescence
In geriatric satellite cells restores quiescence and muscle regenerative functions
What are possible causes of stem cell ageing?
Intrinsic stem cell ageing
Ageing of the local microenivronment/ niche
Ageing of the systemic environment
How might you delay ageing?
Parabiosis: Rejuvenation of muscle regeneration was shown in aged mice exposed to young mouses circulatory system (by attaching them) due to circulating factors from the younger mouse
Calorie restriction: increases mitochondrial content and
upregulates oxidative metabolism in muscle stem cells as well as increasing muscle regeneration and stem cell engraftment
What is the Hayflick phenomenon?
Human cells from the embryonic tissue can only divide a finite number of times. The Hayflick limit is where they stop dividing
How do we identify satellite cells in the lab?
Markers on the cell membrane (beta 1 integrin and CXCR4) are labelled with antibodies which are stained.
Fluorescence-activated cell sorting can be used to find out the number of satellite cells
