1. Chapter 6 The Muscular System
Essentials of Human Anatomy & Physiology
Elaine N. Marieb
Chapter 6 The Muscular System
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

2. The Muscular System
Muscles are responsible for all types of body movement – they contract or shorten and are the machine of the body
Three basic muscle types are found in the body
Skeletal muscle
Cardiac muscle
Smooth muscle

3. Skeletal Muscle Characteristics
Most are attached by tendons to bones
Cells are multinucleate
Striated – have visible banding
Voluntary – subject to conscious control
Slide 6.3
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4. Function of Muscles Produce movement Maintain posture Stabilize joints
Generate heat
Slide 6.8
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5. Connective Tissue Wrappings of Skeletal Muscle
Endomysium – around single muscle fiber
Perimysium – around a fascicle (bundle) of fibers
Figure 6.1
Slide 6.4a
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6. Connective Tissue Wrappings of Skeletal Muscle
Epimysium – covers the entire skeletal muscle
Fascia – on the outside of the epimysium
Figure 6.1
Slide 6.4b
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7. Skeletal Muscle Attachments
Epimysium blends into a connective tissue attachment
Tendon – cord-like structure
Aponeuroses – sheet-like structure
Sites of muscle attachment
Bones
Cartilages
Connective tissue coverings
Slide 6.5
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8. Muscles and Body Movements
Movement is attained due to a muscle moving an attached bone
Figure 6.12
Slide 6.30a
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9. Muscles and Body Movements
Muscles are attached to at least two points
Origin – attachment to an immovable bone
Insertion – attachment to a movable bone
Figure 6.12
Slide 6.30b
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10. MUSCLE CONTRACTION THE PLAYERS: Myosin – thick myofilament
Actin – thin myofilament w/ active sites
Troponin - bodyguard
Tropomyosin - bodyguard
Ca+ - friends w/ troponin, exposes active sites
Na+ - triggers release of Ca+
Neurotransmitter - Acetylcholine (ACh) – loosens up sarcolemma
ATP

11. Neuromuscular Junction – What’s Your Function?
STEPS OF A MUSCLE CONTRACTION:
Nerve impulse releases Ach into synaptic cleft
This opens sodium channels and allows Na+ into muscle
This triggers release of Ca+ from storage sacs
Ca+ attaches to troponin, moving the tropomyosin to expose active site of actin
Myosin attaches to actin and CONTRACTION occurs!!!

12. The Sliding Filament Theory
Go to HANDOUT!
Figure 6.8
Slide 6.18
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13. Types of Muscle Contractions
Isotonic contractions
Myofilaments are able to slide past each other during contractions
The muscle shortens
Isometric contractions
Tension in the muscles increases
The muscle is unable to shorten
Slide 6.28
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14. Effects of Exercise on Muscle
Results of increased muscle use
Increase in muscle size
Increase in muscle strength
Increase in muscle efficiency
Muscle becomes more fatigue resistant
Slide 6.31
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15. Types of Muscles
Prime mover – muscle with the major responsibility for a certain movement
Antagonist – muscle that opposes or reverses a prime mover
Synergist – muscle that aids a prime mover in a movement and helps prevent rotation
Slide 6.35
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16. Naming of Skeletal Muscles
Direction of muscle fibers
Example: rectus (straight)
Relative size of the muscle
Example: maximus (largest)
Slide 6.36a
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17. Naming of Skeletal Muscles
Location of the muscle
Example: many muscles are named for bones (e.g., temporalis)
Number of origins
Example: triceps (three heads)
Slide 6.36b
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18. Naming of Skeletal Muscles
Location of the muscles origin and insertion
Example: sterno (on the sternum)
Shape of the muscle
Example: deltoid (triangular)
Action of the muscle
Example: flexor and extensor (flexes or extends a bone)
Slide 6.37
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19. Head and Neck Muscles Slide 6.38 Figure 6.14
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20. Trunk Muscles Slide 6.39 Figure 6.15
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21. Deep Trunk and Arm Muscles
Figure 6.16
Slide 6.40
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22. Muscles of the Pelvis, Hip, and Thigh
Figure 6.18c
Slide 6.41
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23. Muscles of the Lower Leg
Figure 6.19
Slide 6.42
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24. Superficial Muscles: Anterior
Figure 6.20
Slide 6.43
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25. Superficial Muscles: Posterior
Figure 6.21
Slide 6.44
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