Muscle Physiology and Function

Types of Muscle Tissue

• Skeletal Muscle Tissue (Striated Muscle)
  • Voluntary muscle, controlled by nervous system
  • Multinucleated, striated, and parallel fibers
  • Attached to bones, helps move skeleton
• Smooth Muscle Tissue (Non-Striated Muscle)
  • Involuntary muscle, not controlled by nervous system
  • Spindle-shaped, single nucleus, and non-striated fibers
  • Found in internal organs, helps move substances through organs
• Cardiac Muscle Tissue
  • Involuntary muscle, not controlled by nervous system
  • Striated, branching fibers, and single nucleus
  • Found in heart, pumps blood throughout body

Muscle Physiology

• Muscle Fiber Types
  • Slow-Twitch (Type I)
    • High endurance, low force, and slow contraction speed
  • Fast-Twitch (Type II)
    • High force, low endurance, and fast contraction speed
• Muscle Contraction
  • Sliding Filament Theory
    • Actin and myosin filaments slide past each other to contract muscle
  • Neuromuscular Junction
    • Chemical signal from neuron triggers muscle contraction
• Muscle Energy Production
  • Anaerobic Respiration
    • No oxygen required, produces lactic acid
  • Aerobic Respiration
    • Oxygen required, produces ATP and water

Muscle Function

• Muscle Movement
  • Concentric Contraction
    • Muscle shortens, joint moves
  • Eccentric Contraction
    • Muscle lengthens, joint moves
• Muscle Roles
  • Support and Stability
    • Maintains posture and joint stability
  • Movement and Locomotion
    • Enables movement and locomotion
  • Regulation of Body Functions
    • Helps regulate body temperature, digestion, and circulation