Muscular System

4 Properties of Muscles

• Excitability

• Contractibility

• Extensibility

• Elasticity

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Functions of the Muscular System

1. Maintaining posture

   1. Spine(?)

2. Supporting soft tissue

3. Movement

   1. Voluntary
   2. involuntary
   3. heart muscles
   4. runnings

4. Guarding entrances and exits of the body

   1. Opening mouth
   2. ‘Making a deposit

5. Generate heat and maintain body temp

   1. shivering

Types of Muscle Tissue

• Cardiac Muscle

  • Characteristics
  • Striated
  • Involuntary movement
  • Structure
  • Proteins for striations (sarcerations)
    • Thick = Actin
    • Thin = Myiacyn
  • Short, cylindrical-shaped, branched cells
    • They break off from each other.
  • Un-nucleated
  • Fibers are formed to create a network
  • Cells connect to each other at intercalated discs
    • Connects the cells together.
  • Location
  • Makes up walls of the wall
  • How do they work?
  • Contract quickly and rhythmically.

• Visceral (smooth) Muscle

  • Characteristics
  • Involuntarily contracted
  • Non-striated
  • Structure
  • Flat, short, spindle-shaped cells
  • Uni-nucleated
  • Fibers are arranged to form sheets
  • Location
  • Lines internal organs, and vessels
  • How do they work?
  • Pull action = Peristalsis.

• Skeletal Muscle

  • Characteristics
  • Striated
  • Voluntarily controlled
  • Attached to bones movement of fibrous tissue
  • Structure
  • Lond, cylindrical shaped cells
  • Multinucleated
  • Fibers are arranged to form bundles. Many bundles are in a Fascicle.
  • Location
  • Entire body
  • How do they work?
  • Contract quickly, but can’t stay contracted for long.

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Muscle Movement

• Origin
  • Start of muscle
  • ^^Fixed^^
• Insertion
  • End of the muscle
  • The part that ^^actually moves^^
• Prime Mover
  • Muscle that ^^creates^^ the action
• Synergists
  • Help the movement happen
• Antagonist
  • Muscle that ^^opposes^^ the action

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Range of Motion

• Abduction
• Adduction
• Flexion
• Extension
• Elevation
• Depression
• Rotation
• Circumduction
• Supination
• Pronation
• Dorsiflexion
• Plantar Flexion

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