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• Skeletal muscle


  Attached to bones, striated, voluntarily controlled
• Cardiac muscle


  Located in the heart, striated, involuntarily controlled
• Smooth muscle


  Located in blood vessels and hollow organs, non-striated, involuntarily controlled
• Comparison of Skeletal, Cardiac, and Smooth Muscles

  • Body location
  • Cell shape and appearance
  • Connective tissue components
  • Regulation of contraction
  • Speed of contraction
  • Rhythmic contraction
• Skeletal muscle


  • Constitutes approximately 40% of body weight
  • Attached to the skeletal system
  • Some attach to skin or connective tissue sheets
• Skeletal muscle


  • Also called striated muscle due to transverse bands or striations
• Connective tissue coverings of skeletal muscle

  • Epimysium
  • Perimysium
  • Endomysium
• Muscle fiber


  Single cylindrical cell with several nuclei located at its periphery<|>Range in length from 1 cm to 30 cm and are generally 0.15 mm in diameter
• Muscle fiber


  • Sarcolemma (cell membrane) has many tubelike inward folds called transverse tubules or T tubules
  • T tubules occur at regular intervals and extend into the center of the muscle fiber
  • T tubules are associated with enlarged portions of the smooth endoplasmic reticulum called the sarcoplasmic reticulum
• Sarcoplasm


  Cytoplasm of a muscle fiber which contains many bundles of protein filaments
• Myofibrils


  Bundles of protein filaments consisting of the myofilaments actin and myosin
• Muscles of the head and neck

  • Facial muscles
  • Mastication or chewing muscles
  • Tongue muscles
  • Swallowing muscles
  • Eye muscles
• Chewing muscles


  • Masseter - closes the jaw by elevating and pushing the mandible anteriorly
  • Temporalis - elevates and draws mandible posteriorly
  • Pterygoid - lateral pushes the mandible anteriorly and depresses mandible, medial pushes the mandible anteriorly and elevates mandible
• Tongue and swallowing muscles

  • Intrinsic tongue muscles - change the shape of the tongue
  • Extrinsic tongue muscles - move the tongue
  • Suprahyoid muscles - elevate or stabilize the hyoid bone
  • Infrahyoid muscles - depress or stabilize the hyoid bone
• Deep neck muscles


  • Neck flexors - originate on the anterior side of the vertebra and flex the head and neck
  • Neck extensors - originate on the posterior side of the vertebra and extend the head and neck
• Thoracic muscles


  • Scalenes - elevate the ribs during inspiration
  • External intercostals - elevate ribs for inspiration
  • Internal intercostals - depress ribs during forced expiration
  • Diaphragm - moves during quiet breathing
• Abdominal wall muscles


  • Rectus abdominis - compresses abdomen
  • External abdominal oblique - compresses abdomen
  • Internal abdominal oblique - compresses abdomen
  • Transverse abdominis - compresses abdomen