Muscle Physiology Lecture Notes

Muscle Physiology

• Muscle function is a crucial aspect of muscle physiology

Muscle Characteristics

• Muscle tissue types include skeletal, cardiac, and smooth muscle

Skeletal Muscle

• Skeletal muscle has various types, including oxidative and glycolytic muscles
• Ratio of oxidative to glycolytic muscles is dependent on genetics
• Glycolytic muscles:
  • Have 3 types: Type IIa, IIb, and IIx
  • Have fast contraction action
  • Are generally paler in color due to lower amounts of myoglobin and vascularity
  • Utilize anaerobic pathways for energy
  • Not suitable for long-term endurance activities
• Oxidative muscles:
  • Use aerobic processes
  • Suitable for long-term endurance activities
  • Are highly vascular and have more myoglobin

Skeletal Muscle Types

• Type I fibers:
  • Have slow contraction time
  • Have small motor neurons
  • Have high resistance to fatigue
  • Suitability for long-term aerobic activities
• Type IIa fibers:
  • Have moderately fast contraction time
  • Have medium-sized motor neurons
  • Have fairly high resistance to fatigue
  • Suitability for short-term anaerobic activities
• Type IIx fibers:
  • Have fast contraction time
  • Have large motor neurons
  • Have intermediate resistance to fatigue
  • Suitability for short-term anaerobic activities
• Type IIb fibers:
  • Have very fast contraction time
  • Have very large motor neurons
  • Have low resistance to fatigue
  • Suitability for short-term anaerobic activities