Skeletal Muscle in Ageing

Question 1

What is sarcopenia

Answer 1

irreversible age-related muscle atrophy

Question 2

What is the opposite of hypertrophy (structural proteins added to muscle cell)?

Answer 2

Atrophy (loss of structural proteins from skeletal muscle fibres)

Question 3

why does muscle atrophy occur?

Answer 3

due to disuse

Question 4

How do we combat muscle atrophy

Answer 4

exercise

Question 5

In what kind of athlete is sarcopenia more obvious?

Answer 5

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.

Question 6

What are possible causes of sarcopenia?

Answer 6

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.

Question 7

What kind of muscle fibres are more abundant in old people?

Answer 7

Slow oxidative

Question 8

Can sarcopenia be delayed?

Answer 8

To some extent by exercise, as training adds structural proteins and causes cellular changes that can offset the effects of atrophy.

Question 9

What does exercise do to muscles?

Answer 9

produce greater numbers of cellular mitochondria

increase capillary density

increase the mass and strength of connective tissue.

Question 10

In who are the effects of sarcopenia more pronounced?

Answer 10

People who are sedentary

Question 11

What problems can result due to sarcopenia?

Answer 11

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.

Question 12

What is muscle atrophy?

Answer 12

the number of sarcomeres and myofibrils disappear (but not the number of muscle fibers).

Question 13

Around when does decline in muscle mass start?

Answer 13

As early as 25

Question 14

What factors contribute to muscle aging?

Answer 14

Decreased proliferative ability of muscle cells and the adverse effects of oxidative stress that can cause premature muscle aging.

Question 15

How might we reverse muscle aging?

Answer 15

Genetically silencing p16INK4a, a regulator of cellular senescence

In geriatric satellite cells restores quiescence and muscle regenerative functions

Question 16

What are possible causes of stem cell ageing?

Answer 16

Intrinsic stem cell ageing

Ageing of the local microenivronment/ niche

Ageing of the systemic environment

Question 17

How might you delay ageing?

Answer 17

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

Question 18

What is the Hayflick phenomenon?

Answer 18

Human cells from the embryonic tissue can only divide a finite number of times. The Hayflick limit is where they stop dividing

Question 19

How do we identify satellite cells in the lab?

Answer 19

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