L5.1: Overview of the Muscular System

• Muscles

  ● Responsible for all types of body movement

  ● Contraction and shortening of muscles are due to the movement of microfilaments

  ● “Machines” of the body
• 3 basic types

  ● Skeletal muscle

  ● Cardiac muscle

  ● Smooth muscle
• ADDITIONAL INFORMATION

  Skeletal and smooth muscles are elongated. Hence, they are called the muscle fibers.
• Terminologies / Prefixes

  ● Myo- and mys- (“muscle”)

  ● Sarco- (“flesh”)

  ● Epi- (“upon” “over” “above”)
• Skeletal

  • Body location: attached to bones or, for some facial muscles, to skin
  • Cell shape and appearance: single, very long, cylindrical, multinucleate cells with very obvious striations
  • Connective tissue components: epimysium, perimysium, and endomysium
  • Regulation of contraction: voluntary via nervous system controls
  • Speed of contraction: slow to fast
  • Rhythmic contraction: no
• Cardiac

  • Body location: walls of the heart
  • Cell shape and appearance: branching chains of cells, uninucleate, striations, intercalated discs
  • Connective tissue components: endomysium attached to the fibrous skeleton of the heart
  • Regulation of contraction: involuntary, internal heart pacemaker, nervous system controls, hormones
  • Speed of contraction: slow
  • Rhythmic contraction: yes
• Smooth

  • Body location: walls of hollow organs (other than the heart)
  • Cell shape and appearance: single, fusiform, uninucleate, no striations
  • Connective tissue components: endomysium
  • Regulation of contraction: involuntary, nervous system controls, hormones, chemicals, stretch
  • Speed of contraction: very slow
  • Rhythmic contraction: yes, in some