MCB 150 Lecture 5: Muscle fiber types

• School: University of Illinois
• Department: Molecular and Cell Biology
• Course: MCB 150
• Professor: B Mehrtens

Document Summary

Know the 3 muscle fiber types and metabolic differences. Muscle fiber type is made up of motor (myosin) that forms the thick filament. Different muscles have different ratio of fiber types correlating with muscle activity and action. Increase in motor units participation when shortening or lengthening muscles. Less contraction time less power produced. Most resistant to fatigue and has maximum duration of use. Produce a fast, powerful contraction with atp produced in aerobic cellular respiration. Delivery rate of nutrients and oxygen is lower than in slow oxidative fibers. Most contraction time more power produced. Easily fatigable and has minimum duration of use. Uses glucose in creating phosphate and atp as an immediate source of energy to quickly contract. Large glycogen reserves for supplying glucose for glycolysis. Slow-twitch oxidative muscle fibers: smaller diameter, darker color due to myoglobin; fatigue-resistant. Fast-twitch glycolytic muscle fibers: larger diameter, paler color; easily fatigued. Understand anaerobic and aerobic metabolism in muscle https://youtu. be/i2nobdxmdre.