Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Z MD1 locomotor and exercise block > skeletal muscle in ageing and disease > Flashcards

skeletal muscle in ageing and disease Flashcards

1
Q

what is the relationship of the type of muscle fibre and whether or not is fatigueable easily

A

larger, faster muscle fibres fatigue more easily than smaller, slower muscle fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the principle of muscle malleability

A

muscle fibres can exist as pure type 1, pure type 2 or a mixture of the 2 - and can change during time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

interventions for muscle wasting disorders need to…

A
  • attentuate muscle atrophy
  • promote muscle strength
    (but NOT increase muscle fatigue)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

why is giving anabolic steriods to patients with muscle wasting disease a bad idea

A

because despite causing an increase in the muscle bulk, it will cause increased fatigue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is myostatin

A

a negative regulator of muscle mass

- causes inhibition of proliferation and differentiation of myoblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the biggest problems regarding cancer cachexia

A

it reduces the patients QoL and impairs responses to chemo and radiotherapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is critical illness myopathy

A

inflammatory environment sets off a cascade of signalling pathways that change the balance between synthesis and degredation of protein in favour of degredation occurring over a short period of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is sarcopenia

A

age associated loss of skeletal muscle mass and function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what causes sarcopenia

A
  • disuse
  • changing endocrine function
  • chronic disease
  • inflammation
  • insulin resistance
  • nutritional deficiency
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

diagnosis of sarcopenia should be considered in all older people with..

A

observed declines in physical function, strength or overall health

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

which signs are consistent with a diagnosis of sarcopenia

A
  • gait speed of less than 1m/s
  • unable to stand from a chair unassisted
  • bed bound
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

who do you diagnose sarcopenia

A

low muscle mass + either low muscle strength or low physical performance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

why is sarcopenia a bad thing

A
  • gradually loose their independence

- because it puts the patient at a high risk of mortality, falls, institutionalisation and hospitalisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is muscle weakness

A

an inability to develop an initial force appropriate for the circumstances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

beyond what age does the muscle strength decrease

A

around the age of 50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

are fast or slow muscles more affected by loss of force producing capacity

A

fast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

explain the age related motor unit remodelling

A

denervation of type 2 motor units –> can either lead to:

  • atrophy and death of the fibes
  • reinnervation by type 2 motor units to change the fibres to slow motor fibres
18
Q

which type of fibre is the most susceptible to sarcopenia

A

type 2

19
Q

what occurs before severe muscle wasting in sarcopenia

A

slowing of the muscle contraction

20
Q

why does the slowing of muscle contraction occur

A
  • impaired SR function? - impaired release and reuptake of Ca
  • age related changes in Ca handling
21
Q

what are the features of a motor end plate in someone with sarcopenia

A
  • increase in CT
  • aberrant small diameter axons
  • dysmyelination
22
Q

which hormone is associated with a decreased muscle mass

A

IGF-1

23
Q

what can we do to try and slow sarcopenia

A

do strength training

24
Q

what does strength training do for the elderly

A

causes significant muscle hypertrophy and increased protein turnover
- especially type 2 fibres

25
Q

what is the suggested exercise program for the elderly

A

strength training
aerobic exercise
flexibility
balance

26
Q

what are the hormonal changes with aging that influence muscles

A

decreased circulating levels of anabolic hormones (IGF-1, GF, testosterone)

27
Q

what does the change in hormones during ageing do to the muscles

A

it compromises efficiency of muscle regeneration as a consequence of daily wear and tear

28
Q

when is the onset of duchenne muscular dystrophy

A

early childhood (2-6)

29
Q

symptoms of duchenne muscular dystrophy

A
  • generalized weakness and muscle wasting affecting limb and trunk muscles first
  • calves often enlarged
  • elevated creatine kinase levels
  • Gowers sign
  • lordotic and waddling
30
Q

what is the progression of duchenne muscular dystrophy

A

disease progresses slowly but will affect all voluntary muscles

31
Q

inheritance of duchenne muscular dystrophy

A

x-linked recessive

1 in 3 cases are as a result of a new mutation

32
Q

what is Gowers sign

A

a sign of duchenne muscular dystrophy - have to walk themselves up the floor to get from crawling to standing

33
Q

what causes duchenne muscular dystrophy

A

mutation in the dystrophin gene on Xp21

34
Q

what is dystrophin

A

a cytoskeletal protein - connecting the sarcolemma to laminin in the ECM

35
Q

what 2 important proteins are associated with dystrophin

A

dystrophin associated protein complex

dystrophin glycoprotein complex

36
Q

what is the postulated structural role of dystrophin

A

stabilizing the sarcolemma during muscle contraction, especially during legnthening actions

37
Q

what is the onset of becker muscular dystrophy

A

adolescence or adulthood

38
Q

symptoms of becker muscular dystrophy

A
  • generalized weakness and muscle wasting affecting limb and trunk muscles first
  • calves often enlarged
  • much less severe than Duchennes
  • can have significant heart involvement
39
Q

inheritance of becker muscular dystrophy

A

x linked recessive

40
Q

what causes becker muscular dystrophy

A

abnormal dystrophin protein which is only partly effective

41
Q

what happens as a result of loss of dystrophin

A

disorganised costameres –> instability of the muscle fibres when stretched –> tearing muscle membrane –> enhanced membrane leak–> increased oedema and inappropriate cytosolic Ca and ROS generation –> activates biochemical pathways to breakdown and destroy that muscle fibres

Z MD1 locomotor and exercise block (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions