Muscle Function and Anatomy

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Muscle Function and Anatomy
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Function of Muscle

• Motion of joints
• Movement of body fluids - pump blood, peristalsis
  
• Regulation of body fluids - bladder
• Body stability
• Heat production - 85

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Muscle Architecture
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How Are Muscles Built?

• In circular sections
• Deepest section contains two proteins
• Myosin
• Actin
• Myosin is surrounded by actin

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Myofibrils

• Bundles of actin and myosin

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Muscle Fiber

• Among others things, a muscle fiber contains many
  groups of myofibrils

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Fascicle

• A group of muscle fibers bundled together.

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The Whole Muscle
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The Whole Muscle
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Muscle Membranes
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Tendons

• All 3 membranes converge to form a tendon which
  connects the muscle to the bone

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Muscle Fiber Arrangement p. 25

• Pennate muscles
• Greater cross sectional area greater force
  (strength) production
• Parallel muscles
• Longer muscles greater range of motion

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Muscle Fiber Arrangement
Strap

• Parallel muscles
• Flat (rectus abdominus)
• Fusiform (biceps)
• Strap (sartorius)
• Radiate (trapezius)
• Spincter
• Pennate
• Unipennate (biceps femoris)
• Bipennate (rectus femoris)
• Multipennate (deltoid)

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Types of Muscle Contraction p. 28

• Isometric (Static)
• Isotonic (Dynamic)
• Concentric
• Eccentric

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Types of Muscle Contraction

• Concentric contraction - If muscle force is
  greater than the resistance
• Static or Isometric contraction - If muscle force
  is equal to the resistance
• Eccentric contraction - If muscle force is less
  than the resistance

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Lengthens
Lengthens
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Eccentric Contraction

• Used to control agonist and prevent over
  lengthening of the antagonist.
• Example triceps lowers dumbbell while biceps
  controls the triceps activity (action).
• Causes more damage than other types
• Greater repair required
• producing a stronger muscle
• Also, results in more muscle soreness.

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ROLE OF MUSCLES

• Agonist prime mover
• Antagonist have an action opposite to the
  agonist
• Stabilizers fixate or stabilize the joint
• Synergists assist or guiding
• Neutralizers counteract or neutralize movements

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Agonist and Antagonist
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Types of Muscle Fibers

• Fast twitch
• Slow twitch

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Questions?