TYPES OF MUSCLE FIBRES

• WHAT ARE THE TWO TYPES OF MUSCLE FIBRE?

  slow-twitch and fast-twitch muscle fibres
• SLOW-TWITCH MUSCLE FIBRES DESCRIPTION?

  • contract more slowly
  • less powerful contractions
  • longer period
  • adapted to endurance and aerobic respiration (avoid lactic acid building)
  • e.g. calf muscle
• FAST-TWITCH MUSCLE FIBRES?

  • contract more rapidly
  • more powerful contractions
  • short period
  • adapted to intense exercise and anaerobic respiration
  • e.g. biceps
• ADAPTIONS OF SLOW-TWITCH MUSCLE FIBRES?

  • large myoglobin store
  • rich supply of blood vessels
  • numerous mitochondria
• WHAT DOES MYOGLOBIN DO?

  store oxygen, is a bright red molecule
• WHAT DOES A RICH SUPPLY OF BLOOD VESSELS DO?

  deliver oxygen and glucose for respiration
• ADAPTIONS OF FAST-TWITCH MUSCLE FIBRES?

  • thicker
  • more numerous myosin filaments
  • high concentration of glycogen
  • high concentration of enzymes required for anaerobic respiration
  • store of phosphocreatine
• WHAT DOES PHOSPHOCREATINE DO?

  rapidly generates ATP from ADP in anaerobic conditions
• WHY IS ANAEROBIC RESPIRATION USEFUL IN FAST-TWITCH MUSCLE FIBRES?

  provides ATP rapidly