MUSCLE ADAPTATION, DAMAGE AND REPAIR Flashcards
What is muscle plasticity
The ability of a given muscle to alter its structural and functional properties in accordance with the environmental conditions imposed on it
How does a muscle change in length
Sarcomeres are added or deleted from muscle fibres to maintain optimum sarcomere length therefore optimum performance
What is hyperplasia
Increase in the amount of organic tissue that results from cell proliferation
What is the most potent factor in determining muscle size
Mechanical load
More movement = increased muscle tissue
What do anabolic factors do
Build up muscle
What do catabolic factors do
Decrease muscle mass
What factors can cause muscle growth
Anabolic steroids Growth hormones Insulin Adrenoceptor agonists Thyroid hormones
What factors can cause muscle catabolism
Catabolism - muscle breakdown
Glucocorticoids
Nutritional deprivation
Trauma
What is the most important thing about (muscle) factors
Not all fibre types are affected equally by them
What are the main causes of muscle pathology
- External trauma- crushing and laceration, extremes of hot and col d
- internal trauma- muscle tears due to forceful contractions
- nerve damage
- disease- inflammatory, inherited, nutritional, endocrine
- aging
Describe what is meant by sarcopenia
Atrophy associated with aging
- loss of motor axons
- denervation
- loss of motor fibres
- increase in MU size=loss of dexterity
- fibrosis - build up of connective tissue
Explain the role of satellite cells in the repair and regeneration f muscle fibres
- Activation of satellite cells
- They migrate to the necrotic zone
- Form myotubes
- Fuse with myofibre to repair damage
How can you tell apart regenerated fibres from normal muscle inbred
Regenerated fibres have a central nuclei opposed to it being near the side of the fibre in a normal muscle fibre
What are the effects of endocrine factors on myopathies
Hormonal disorders
- cushing’s disease
- hypothyroidism
- diabetes
What are the effects of nutritional factors in myopathies
Mostly found in herbivores due to selenium of vitamin E deficiency
Lambs and calves of deficient mothers are weak and have impaired movement
