1.04 STRUCTURES OF THE MUSCULAR SYSTEM

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1.04STRUCTURES OF THE MUSCULAR SYSTEM
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The Muscular System

• Comprises nearly half our weight.
• Over 650 muscles.
• Each muscle is made up of hundreds or thousands
  of muscle fibers.

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The Muscular SystemMuscle Fibers

• Bundles of threadlike structures called
  myofibrils
• Composed of
• Myosin- thick myofibrils made of proteins
• Actin- thin myofibrils made of proteins
• Form overlapping pattern called sarcomere
• muscle muscle fiber
• sarcolemma sarcomere
• functional unit of muscle movement

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Structures of the muscular system

• Muscles
• Skeletal
• Smooth
• Cardiac
• Sphincter

• Connective tissue
• Tendons
• Fascia

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Structures of the muscular system

• Types of muscle
• Skeletal
• Smooth
• Cardiac
• Sphincter

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Structures of the muscular system

• Types of Muscle
• SKELETAL MUSCLES
• Attached to bone
• Striated (striped) appearance
• Voluntary
• Multinucleated muscle cell bundles

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Structures of the muscular system

• Types of Muscle
• SMOOTH MUSCLES
• Also known as visceral muscles
• Involuntary
• Located in walls of digestive system, uterus
  blood vessels

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Structures of the muscular system

• Types of Muscle
• CARDIAC MUSCLE
• Found only in the heart
• Striated, branched
• Involuntary
• Cells are fused- when one contracts, they all
  contract, creating the heartbeat

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Structures of the muscular system

• Types of Muscle
• SPHINCTER MUSCLES
• Also called dilator muscles
• Special, circular muscles
• Located in the
• digestive system
• urinary system

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Structures of the muscular system

• Connective tissue
• Tendons
• dense bands that connect skeletal muscle to the
  bone

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Structures of the muscular system

• Connective tissue
• Fascia
• Fibrous connective tissue sheets that wrap around
  muscle bundles

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How do skeletal muscles get their names?

• Location-where
• Size-maxi/mins
• Number of origins
• Number/Location of origin and insertion
• Action
• Shape
• Combination

• However,
• not all muscles are named by the above methods!

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Head Neck Muscles pg. 204-205
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Torso/Trunk pg 204-205(anterior)
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Torso/Trunk(anterior)
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Torso/Trunk(posterior)
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Upper extremities
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Lower extremities