Brainscape's Knowledge GenomeTM

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


See full index

Module 204 MSK & Immune system > T2 L6 Intro to pathophysiology of skeletal muscle > Flashcards

T2 L6 Intro to pathophysiology of skeletal muscle Flashcards

1
Q

What does skeletal muscle respond to in endurance exercise?

A

Total contractile activity

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

What does skeletal muscle respond to in resistance training?

A

Loading and stretch

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

How many muscle fibres in biceps brachii?

A

200,000

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

What happens during hypertrophy in the muscle?

A

Synthesis of myofilaments
Addition of sarcomeres
Satellite cell activation
Angiogenesis and vascularisation

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

What is angiogenesis?

A

Physiological process through which new blood vessels form from pre-existing vessels

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

What adaptions to the muscle does endurance exercise cause?

A

Slight increase in fibre diameter
Increased blood supply to increase oxidative capacity
Increase mitochondrial content
Fibres become slower
Gradual transformation of type IIX to type IIA fibres

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

What adaptions to the muscle does non-endurance exercise cause?

A

Conversion to type IIX from IIA
Increase in numbers of sarcomeres and myofilaments causing an increase in type IIX fibre size leading to increased power
Larger muscles

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

When should ice be used on a muscle?

A

To reduce swelling by reducing perfusion
After acute injury such as a sprain
After exercise in overuse injury

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

What is a sprain?

A

Injury to a ligament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When should heat be used on a muscle?

A

To relax & loosen tissues
Use before activities that irritate chronic injuries such as a strain
Increases blood flow

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

What is a strain?

A

Injury to a muscle or tendon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can cause a strain?

A

Chronic activities which:

  • develop over-stretching of muscle fibres
  • pulling too far on a muscle
  • pulling a muscle in one direction while it is contracting in the other direction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is aspirin used for?

A

Musculoskeletal pain
Chronic disease e.g. osteoarthritis
Sports injuries - combined with ice after exercise

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

What does aspirin do?

A

NSAID

Reduces pain and inflammation

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

What is the mechanism of aspirin?

A

Inhibits COX which reduces synthesis of prostaglandins

Part of arachidonic acid pathway

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

What are the risks of aspirin?

A

Gastro-intestinal adverse effects
Stomach bleeding
Ulcers

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

What are the anabolic effects of testosterone?

A

Increases protein synthesis
Decreases catabolism by opposing cortisol and glucocorticoids
Reduces fat
- increases BMR
- increases differentiation to muscle rather than fat cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the effects of anabolic steroid abuse in males?

A

Testes atrophy
Sterility
Baldness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the effects of anabolic steroid abuse in females?

A

Breast / uterus atrophy
Menstrual changes
Facial hair
Deepening of voice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the effect of space flight on muscles?

A

Decrease in relative muscle mass (predominantly weight-bearing muscles)
Transition of type I fibres to type IIa/X fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the effect of bed rest on muscles?

A 
Transition of type I fibres to type IIA
Weight-bearing muscle atrophy 
 - decrease muscle protein synthesis
 - myofibrillar breakdown
 - decrease in strength 
 - loss of type I fibres
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why does bed rest have an effect on muscles?

A

Reduces hydrostatic pressure gradient in CVS
Reduces muscle force production
Eliminates compression on bones
Lowers total energy expenditure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe the features of type I fibres

A 
Slow contraction
Small 
High fatigue resistance
Aerobic activity
Low power
High mitochondrial density
High capillary density
High oxidative capacity
Low glycolytic capacity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Describe the features of type IIA fibres

A 
Moderately fast contraction
Medium 
Long-term anaerobic activity
Medium power
High mitochondrial density
Intermediate capillary density
High oxidative capacity
High glycolytic capacity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Describe the features of type IIX fibres

A 
Fast 
Large 
Short-term anaerobic
High power
Medium mitochondrial density
Low capillary density
Intermediate oxidative capacity
High glycolytic capacity
26
Q

Describe the features of type IIB fibres

A 
Very fast contraction
Very large
Low resistance to fatigue
Short-term anaerobic activity
Very high power
Low mitochondrial density
Low capillary density
Low oxidative capacity
High glycolytic capacity
27
Q

How do muscles regenerate during inflammation & degeneration of damaged muscle tissue?

A

Previous quiescent myogenic cells (satellite cells) are activated
Proliferate, differentiate and fuse on extant fibres
Contribue to forming multinucleate myofibres

28
Q

What is HGF?

A

Hepatocyte growth factor

Paracrine cellular factor important in myogenesis and muscle regeneration

29
Q

What is caveolin 1?

A

Integral membrane protein which is involved in receptor-independent endocytosis

30
Q

What are myosatellite cells?

A

Progenitor cells in muscles (satellite cells)
Essential for regeneration and growth
Most are quiescent and activated by mechanical strain to proliferate and differentiate

31
Q

What is myalgia?

A

Muscle pain

32
Q

What causes myalgia?

A

Injury
Overuse
Infections
Auto-immune

33
Q

What is myopathy?

A

Muscular weakness due to muscular muscle fibre dysfunction

34
Q

What is paresis?

A

Weakness of voluntary movement or partial loss of voluntary movement or impaired movement

35
Q

What are fasciculations?

A

Involuntary visible twitches in single motor units
Commonly occur in motor neuron disease
Appear as brief ripples under skin

36
Q

What are fibrillations?

A

Involuntary spontaneous contractions of individual muscle fibres

37
Q

What is rhabdomyolysis?

A

Rapid breakdown of skeletal muscle

38
Q

What are the causes of rhabdomyolysis?

A 
Trauma
Drugs - statins or fibrates
Hyperthermia
Ischaemia to skeletal muscle
 - compartment syndrome
 - thrombosis
39
Q

What is compartment syndrome?

A

Increased pressure within one of body’s compartments which contains muscles & nerves

40
Q

What are the symptoms of rhabdomyolysis?

A

Myalgia
Vomiting & confusion
Darkened urine

41
Q

Why is there a risk of kidney failure in rhabdomyolysis?

A

Cellular proteins (especially myoglobin) is released into the blood and clots renal glomeruli
Urine becomes tea coloured, no urine production 12h after injury
Leads to hyperkalaemia

42
Q

What is the treatment for rhabdomyolysis?

A

Intravenous fluids to treat shock

Haemodialysis

43
Q

What is the CPK isoform in skeletal muscle?

A

CK-MM

44
Q

What is the CPK isoform in cardiac muscle?

A

CK-MB

45
Q

What does myoglobin do?

A

Buffers O2

46
Q

Why does rigor mortis occur?

A

ATP is depleted after death
Muscle cell doesn’t re-sequester Ca2+ in SR leading to increase in cytosolic Ca2+
Ca2+ allows cross-bridge cycle contraction until ATP and creatine-phosphate run out.
Without ATP the myosin stops after the power stroke and is still bound to actin

47
Q

When does rigor mortis end?

A

When muscle tissue degrades after 3 days

48
Q

What is myasthenia gravis?

A

Progressive muscle weakness and fatiguability

Depletion of nicotinic acetylcholine receptor

49
Q

What are the symptoms of myasthenia gravis?

A

Ptosis
Diplopia
Weakness in eyelid and extraoccular muscles
Dysphagia

50
Q

What are the treatment options for myasthenia gravis?

A 
AChE inhibitors e.g. neostigmine
Edrophonium
Thymectomy
Immunosuppressive drugs
Plasmapheresis
51
Q

How does neostigmine help myasthenia gravis?

A

Increases ACh activity at NMJ –> ACh released from nerve terminals into synapse aren’t catabolised –> bind to remaining AChR for a long time

52
Q

What is plasmapheresis?

A

Removal of anti-AChR antibodies from bloodstream

53
Q

What is spinal muscular atrophy?

A

Floppy baby syndrome

Death of lower motor neurons in anterior horn of spine

54
Q

What causes spinal muscular atrophy?

A

Genetic defect
SMN1 gene
Autosomall recessive

55
Q

What is malignant hyperthermia?

A

Rare genetic susceptibility to gas anaesthetics

Mutation in RyR + gas anaesthetic leads to Ca2+ release

56
Q

Describe the process occurring in malignant hyperthermia

A

Ca2+ release
SERCA works too hard to pump Ca2+ back into SR
Increase O2 consumption –> increased CO2 –> acidosis, tachypnoea, muscles & body overheat –> muscles are damaged –> hyperkalaemia –> muscles become rigid

57
Q

What treatment can be used in malignant hyperthermia?

A

Dantrolene sodium can stop abnormal calcium release by inhibiting ryanodine receptor

58
Q

What are muscular dystrophies?

A

Group of inherited disorders

Severe and progressive muscle wasting

59
Q

What is Duchenne muscular dystrophy?

A

Progressive loss of muscle tissue which is replaced by fibrofatty connective tissue
Mutation of gene for dystrophin protein
X-linked
Gower’s sign

60
Q

What is Gower’s sign?

A

Patient has to use hands and arms to walk up own body to stand up
Indicates weakness of hip and thigh muscles associated with muscular dystrophy

Module 204 MSK & Immune system (44 decks)

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