muscle structure/fatigue Flashcards
1
Q
muscle hierarchy
A
epimysium –>muscle –>perimysium –>fascicle –>endomysium –>fiber –>myofibril
2
Q
structure of sarcomere
A
- myosin: thick filaments
- actin: thin filament
- tropomyosin/troponin: reg protein on actin
- m line: hold myosin in alginment
- z line: holds actin
- H zone: includes m line, only myosin
- I band: just z line and actin
- A band: overlap of thick and thin filaments
3
Q
muscle fatigue depends on
A
type of ex
muscle fiber type
fitness and nut status
4
Q
peripheral site of muscle fatigue
3 of them
A
- neuromscular junction (NMJ)
- t-tube and SR
- contractile elements
5
Q
why do you have fatigue at NMJ?
3 of them
A
- inhib axon term
- depletion of NT
- altered NT binding to receptors
6
Q
why do you have fatigue at t tube and SR?
2 of them
A
- inability to release Ca
- inability to bind to troponin
7
Q
why do you have fatigue at contractile elements?
4 of them
A
- depletion of ATP
- depletion of PCr (mostly for type II fibers)
- depletion of glycogen (mostly for type I fibers)
- accumulation of lactate
8
Q
central sites for msucle fatigue and why
A
- central nervous system
- why?
- malfunction of neurons
- inhibition of voluntary effort
- psychological factors
9
Q
probable causes of fatigue in long term mod to heavy sub max exercise
A
- depletion og glycogen
- accumulation of H+
- decrease in Ca release
10
Q
steps for muscle regeneration
A
- FGF and IGf-1 call WBCs to repair area
- FGF and IGF-1 activate satellite cells
- cells become mitotically active
- align w/ eachother and fuse together
- myotube forms
- myotube converts from 1st degree to 2nd degree
- go from embryonic to neonatal to adult fibers
11
Q
what are cytokines and what do they do?
A
- secreted by nervous and immune system
- serve as messengers btwn cells
- reg inflam response
12
Q
what is interleukin 6
A
- cytokine found to be essential to muscle growth in response to exercise
- stimulates proliferation of satellite cells
