15.7 structure of skeletal muscle Flashcards
1
Q
what are skeletal muscles?
A
attached to bones & acts under voluntary, conscious control
2
Q
describe from the largest to smallest, the muscle structure.
A
whole muscle -> bundle of muscle fibres -> single muscle fibre -> myofibril -> sacromere
3
Q
what are myofibrils made up of?
A
action & myosin
4
Q
what is the I-band?
A
non-overlapping region
5
Q
what is the A-band?
A
overlapping thin & thick regions
6
Q
what is the H-zone?
A
region of thick filaments (myosin) only
7
Q
what is the Z-line?
A
separates sarcomeres
8
Q
what are slow-twitch fibres adapted for?
A
aerobic respiration & slow contraction
9
Q
what are 3 other features of slow-twitch fibres?
A
- large store of myoglobin (bright-red)
- rich supply of blood vessels (for gas exchange)
- lots of mitochondria for ATP production
10
Q
what are fast-twitch fibres adapted for?
A
anaerobic respiration & rapid contraction
11
Q
what are other 3 features of fast-twitch fibres?
A
- thicker & more myosin filaments
- high conc. of glycogen
- high conc. of enzymes needed in anaerobic respiration
