Muscles - Anatomy & Physiology

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Introduction

Muscular contraction is necessary for voluntary and involuntary movement of limbs, stabilization of joints, maintaining luminal diameter (in the case of arteries, bowel, etc), and to produce heat. Three types of muscle can be described:

• Skeletal (aka Striated, Somatic, Voluntary)
• Smooth (aka Visceral)
• Cardiac

Skeletal Muscle

• Skeletal muscle includes muscles of:
  • Posture
  • Movement
  • Respiration

• Two basic types of skeletal myofibre:
  • Type I
    • Grossly red
    • High myoglobin level
    • Slow rate of contraction
    • High oxidative activity
    • Function - postural
  • Type II
    • Grossly white
    • Low myoglobin level
    • Fast rate of contraction
    • High glycolytic activity
    • Function - exercise

• Each muscle is composed of multiple fascicles
  • Each fascicle is composed of multiple polygonal myofibres

Tendon

Histology of tendon (Courtesy of RVC Histology images)

• Consists of dense collagen type 1 fibres and fibroblasts (tenocytes)

Links

• Muscle Pathology
• Bursae and Tendons Pathology

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