Sarcopenia & DMD

Question 1

define sarcopenia and what is needed for diagnosis?

Answer 1

age-associated loss of skeletal muscle mass and function.

Diagnosis = low muscle mass + low muscle strength or low physical performance

Question 2

what happens in regard to the muscle fibre types in sarcopenia and what age does this begin.

Answer 2

from 50 fast twitch fibres start to become replaced by slow twitch.

Question 3

name 4 exercise types that can aid in healthy aging

Answer 3

strength training, aerobic, flexibility, balance

Question 4

which type of hormones decline with age? list 3 and how they impact muscle wasting

Answer 4

anabolic - GH, IGF-1 and testosterone. Low levels compromise the efficiency of muscle regeneration as a consequence of damage from daily wear and tear

Question 5

what does myostatin do?

Answer 5

inhibit muscle growth

Question 6

what do DMD & BMD stand for

Answer 6

Duchenne & Becker Muscular Dystrophy

Question 7

describe the clinical course of DMD

Answer 7

onset in males age 2-6. originally hypertrophied calves & Gowers Sign (struggle to get up from floor). Limb and trunk wasting first (wheelchair bound 7-12) then eventually all other muscles (except extraoccular) so usually die of respiratory problems in 20s

Question 8

describe genetics and pathology of DMD

Answer 8

X lnked recessive causes lack of the protein dystrophin. Lack of this protein affects muscles ability to regenerate after contraction damage.

Question 9

differences between DMD & BMD (clinical and molecular)

Answer 9

BMD less severe with later onset (adolescence or adulthood) and slower progression. Survival well into mid-late adulthood.
In BMD there is abnormal, smaller amounts of dystrophin c.f. absolutely none in DMD