Muscles Twitch Fibres
- Created by: Gemma
- Created on: 27-02-14 20:29
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- Muscles twitch fibres
- FAST TWITCH FIBRES
- FEATURES
- Contracts more rapidly
- powerful contraction for a short period of time
- quickly become fatigued- lactate accumulates rapidly
- adapted to intense exercise e.g. weight training
- STRUCTURE
- very little myoglobin- muscle appears lighter colour
- ATP largely obtained from glycolysis (from ATP previously made)
- fewer blood capillaries
- large store of Ca2+ ions
- high rate of ATP hydrolysis in myosin heads- store of phosphocreatine to generate ATP in anaerobic conditions
- FEATURES
- SLOW TWITCH FIBRES
- FEATURES
- Contract more slowly
- less powerful contractions over a longer period of time
- resistant to fatigue
- Adapted to endurance work e.g. Marathon running
- STRUCTURE
- large store of myoglobin (bright red) molecule that stored O2 accounts for red colour of slow twitch
- supply of glycogen- stored of energy for aerobic respiration
- rich supply of capillaries to supply glucose and O2 to fibres
- numerous, large mitochondria
- smaller stored of Ca2+ in tubules
- slower rate of ATP hydrolysis in myosin heads
- FEATURES
- Antagonistic Muscles
- Muscles can pull they cannot push. muscles are attached to bone by inelastic tendons
- muslces work in ANTAGONISTIC PAIRS- when one contacts one relaxes. A flecor muscles bends at a joint, an extensor muslces straigjtens it eg biceps and triceps
- FAST TWITCH FIBRES
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