Lecture 15 - Exercise: Muscle Bone And Systemic Changes Flashcards Preview

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Flashcards in Lecture 15 - Exercise: Muscle Bone And Systemic Changes Deck (16):

Muscle fatigue

- reversible weakness associated with intense actibity
- eg: run up a mountain


Muscle damage

- mild self repairing condition
- muscular dystrophy is characerised by greatly increased stretch induced damage
- eg: run down a mountain


Delayed onset msucle soreness

- a form of muscle damage
- reduced force, takes days to recover
- loss of muscle enzymes in the blood
- overstretched sarcomeres

- mainly occurs in contractions involving stretching


When are sarcomere unstable

- on the descending aspect of the tension length curve


Satellite cell activation and regeneration

- SM contain satellite cells which can divide, form new muscle cells and fuseto form a replacement multinucleate muscle fiber


Exercise induced hypertrophy : How

- may involve exercise-induced muscle damage
- involves increased protein synthesis, reduced protein breakdown
- myofibrils thicken
- increased number of sarcomeres
- synthesis of more muscle proteins


Exercise and formation of bone

- exercise promotes laying down of new bone more distally


Cardiovascular response: why does HR increase

- withdrawal of PNS activity
- increased SNS activity


Systemic changes in exercise

- systemic wide vasoconstriction but local vasodilation


Muscle mass and VO2

- there is a linear relationship between the total amount of power produced and the amount of oxygen required for taht production of power in one muscle


Substrates and ATP generation changes over time

- non oxidative pathway initially and then the glycolysis pathway kicks in
- after 6 hours of exercise, there is a major shift away from glucose oxidation to FA oxidation over time


Substrates and ATP generation changes with intensity

- the amount of energy required to support more activity
- optimal fat burning range is around 65%
- if you work harder, more utilisation of muscle glycogen


Duchenne muscular dystrophy

- 1 in 3500 male birth
- muscle nromal at birth and then increasing muscle weakness with age
- mild intellectual impairment
- cardiac involvement


Why does absence of dystrophin cause muscle damage

- dystrophin is a cytoskeletal protein which connects the contractile proteins to a group of proteins in the cell membrane
- dystrophic muscle is more susceptible to stretch induced muscle damage


Exercise as a therapeutic modality

- increased energy expenditure decreases lipid content thereby reducing the processes that inhibits insulin signalling
- increased utilisation of glucose leads to upregulation of processes involved in glucose metabolism
- also net improvement in insulin sensitivity


Cardiac output is worload dependent

Predominanlty due to increased HR and to a lesser extent to SV