Physiology of Whole Skeletal Muscle

Dr. Jack Rosenbluth

Goals

1. To understand the factors that underlie the function of whole skeletal muscle.
2. To understand the factors that differentiate muscle fiber types and how these are related to muscle function.

Outline

1. The motor unit
2. Muscle fiber types
• Slow twitch fibers
• Fast twitch fibers
• Fiber types and motor units
3. Whole muscle physiology
• Series elastic component
• Twitch and tetanic tension
• EMG
4. Trophic responses of skeletal muscle
• Plasticity
• Response to exercise
• Recruitment
5. Comparative physiology of whole skeletal muscle
• Fowl pectoral muscle
• Fish compared to sloth muscle

For Review

Define or Explain

• motor unit
• series elastic component
• tetanic contraction
• twitch contraction
• slow and fast twitch fibers
• "red" and "white" fibers

Briefly Answer

• What is the basis for the staircase phenomenon is muscle tension with increased stimulus frequency?
• Explain why a muscle fiber achieves greater tension through tetanic activation than through a singe twitch.
• Compare the physiologic and structural differences between the leg muscles of a long-distance runner and the arm muscles of a weight-lifter.

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