Muscles & Muscle Tissue

Chapter 10: Muscles & Muscle Tissue

Learning Objectives

• Describe the major functions of muscle tissue.

• Identify skeletal, cardiac, and smooth muscle.

• Describe the structure, location, and function of skeletal, cardiac, and smooth muscle.

• Compare and contrast the characteristics of skeletal, cardiac, and smooth muscle.

• Define tension and contraction.

• Describe the organization of muscle tissue.

• Name connective tissue layers: epimysium, perimysium, and endomysium.

• Describe a skeletal muscle fiber, including T tubules, sarcoplasmic reticulum, and myofibrils.

• Explain the organization of a myofibril.

• Name and describe the function of contractile, regulatory, and structural protein components of a sarcomere.

• Describe the anatomy of the neuromuscular junction.

• Explain excitation-contraction coupling.

• Explain the sliding filament theory of muscle contraction.

• Describe the sequence of events in the contraction cycle of skeletal muscle.

• Explain how an electrical signal arrives at the neuromuscular junction.

• Describe the events at the neuromuscular junction that elicit an action potential.

• Explain factors contributing to muscle fatigue.

• Summarize events during the recovery period of muscle contraction.

• Define motor unit.

• Interpret myograms and explain treppe, summation, and tetanus.

• Interpret myograms and explain recruitment.

• Interpret graphs of the length-tension relationship.

• Demonstrate isotonic and isometric contraction and interpret related graphs.

• Demonstrate concentric and eccentric contraction.

• List the anatomical and metabolic characteristics of fast, slow, and intermediate muscle fibers.

Introduction to Muscles

• Muscles represent nearly half of the body’s mass.

• Muscles transform chemical energy (ATP) into directed mechanical energy, enabling force exertion.

• ATP is produced in mitochondria.

Muscle Functions

• Produce movement:

  • Skeletal muscles facilitate body movement.

  • Cardiac muscle enables blood movement.

  • Smooth muscle affects blood flow at capillary beds and supports vessel walls.

  • Smooth muscles in organs of the digestive, reproductive, and urinary tracts.

• Maintain posture & body position:

  • Skeletal muscle

• Stabilize joints:

  • Skeletal muscle

• Support soft tissues

• Guard body entrances & exits

• Maintain body temperature: Homeostasis, negative feedback

Types of Muscle Tissue

• Skeletal

• Smooth

• Cardiac

Gross Anatomy of Skeletal Muscle

• Origin: Attachment to immovable or less movable bone.

• Insertion: Attachment to movable bone.

• Muscle fiber = skeletal muscle cell

• Muscle fascicle = a bundle of muscle fibers

Connective Tissues of Skeletal Muscle

• Epimysium: