Types of muscle fibre

Question 1

aWhat are the two types of muscle fibre?

Answer 1

• slow twitch muscle = contract slower than fast twitch fibres and provide less powerful contractions over a longer time period
• fast twitch muscle = contract more rapidly and provide more powerful contractions over a short period

Question 2

What is the location and function of slow twitch muscle fibre?

Answer 2

• in humans, they are found most commonly in calf muscles and in the back
• adapted for aerobic respiration for endurance work such as running a marathon

Question 3

What is the location and function of fast twitch muscle fibre?

Answer 3

• For intense exercise like weight lifting
• common in muscles that need short bursts of intense activity like biceps and triceps

Question 4

tHow are slow twitch muscles adapted for their function?

Answer 4

• more myoglobin = a bright red molecule that has a higher affinity for oxygen
• a rich supply of blood vessels = delivers oxygen and glucose for aerobic respiration
• numerous mitochondria to produce ATP

Question 5

How are fast twitch muscles adapted for their function?

Answer 5

• thicker and more numerous myosin filaments
• a high concentration of glycogen
• a high concentration of enzymes that are involved in aerobic respiration which can provide ATP rapidly
• A store of phosphocreatine, can rapidly generate ATP from ADP in anaerobic conditions, providing energy for muscle contraction