5
Lesson 5.1: Muscle Tissue Categories and Functions
Lesson 5.2: Skeletal Muscle Actions
Lesson 5.3: The Major Skeletal Muscles
Lesson 5.4: Common Injuries and Disorders of Muscles
The Muscular System
Lesson 5.1
Muscle Tissue Categories and
Functions
Chapter 5: The Muscular System
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• categories– skeletal– smooth – cardiac
• functions– behavioral properties– tension and types of skeletal muscle contractions
Muscle Tissue
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• skeletal– voluntary– striated
• smooth– involuntary– no striations
• cardiac– involuntary– striated– intercalated disks
Muscle Tissue Categories
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Muscle Tissue Categories
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• sarcolemma and endomysium surrounds the muscle fiber
• perimysium bundles groups of muscle fibers to make up a fascicle
• epimysium encloses several fascicles to make up a muscle
• aponeurosis connects muscle to other tissues
Skeletal Muscle Organization
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Skeletal Muscle Organization
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True or False?
1. Smooth muscle is voluntary.
2. Cardiac muscle has branching fibers.
3. Smooth muscle is multinucleate.
4. Perimysium wraps fascicles to make a muscle.
5. Endomysium surrounds the muscle fibers.
Review and Assessment
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• extensibility–stretch• elasticity–snap back• irritability–respond• contractility–shorten
Behavioral Properties of Muscle
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• tension and types of skeletal muscle contraction– agonist–moves bone– antagonist–opposes the movement of the agonist
Muscle Tissue Functions
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• agonist contracts, antagonist relaxes
Concentric Contraction
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• agonist contracts while lengthening, antagonist relaxes
Eccentric Contraction
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• both agonist and antagonist contract
Isometric Contraction
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Match these words with 1–5 below: extensibility, elasticity, irritability, contractility, agonist, antagonist.
1. respond
2. opposes movement
3. stretch
4. shorten
5. causes movement
Review and Assessment
Lesson 5.2
Skeletal Muscle Actions
Chapter 5: The Muscular System
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• the motor unit• skeletal fiber types• muscular strength, power, and endurance
Skeletal Muscle
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• group of muscle fibers under the control of one motor neuron
The Motor Unit
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• acetylcholine crosses the synaptic cleft at the neuromuscular junction
• depolarization takes place on muscle fiber• action potential begins
Generating Action Potentials
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• sarcomeres shorten by actin filaments sliding along myosin filaments
Contraction of the Sarcomeres
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• action potential always causes entire motor unit muscle fibers to contract
• all-or-none law
Maximum Tension and Return to Relaxation
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True or False?
1. An action potential causes one half of the fibers in the motor unit to contract.
2. Acetylcholine crosses the synaptic cleft at the neuromuscular junction.
3. The sarcomeres lengthen by myosin filaments sliding over actin filaments.
Review and Assessment
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• slow-twitch• fast-twitch
– type IIa– type IIb
Skeletal Muscle Fiber Types
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• parallel fiber arrangements– fusiform– bundled– triangular
• pennate fiber arrangements– unipennate– bipennate– multipennate
Skeletal Muscle Fiber Architecture
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• rotary force that muscles can produce at a joint– the maximum weight you can lift is a measurement of
muscular strength
Muscular Strength
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• force x velocity– how fast you can sprint is a measurement of muscle
power
Muscle Power
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• muscle tension/time– how far you can run is a measurement of muscle
endurance
Muscle Endurance
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Match these words with 1–5 below: muscle endurance, muscular strength, muscle power, Type I, Type IIb.
1. force x velocity
2. muscle tension/time
3. rotary force that muscles can produce at a joint
4. slow twitch, slow fatigue
5. fast twitch, fast fatigue
Review and Assessment
Lesson 5.3
The Major Skeletal Muscles
Chapter 5: The Muscular System
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• directional motions• head and neck muscles• trunk muscles• upper limb muscles• lower limb muscles
The Major Skeletal Muscles
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• origin – fixed end of a muscle
• insertion– movable end of a muscle
Skeletal Muscle Attachments
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• flexion• extension• hyperextension• dorsiflexion• plantar flexion
Sagittal Plane Movements
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• abduction• adduction• inversion• eversion• radial deviation• ulnar deviation
Frontal Plane Movements
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• medial rotation• lateral rotation• pronation• supination
Transverse Plane Movements
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• circumduction• opposition
Multiplanar Movements
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True or False?
1. Circumduction is a multiple plane movement.
2. Supination is a multiple plane movement.
3. The insertion is the fixed end of a muscle.
4. Extension is a sagittal plane movement.
5. Adduction is a frontal plane movement.
Review and Assessment
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Head and Neck Muscles
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Trunk Muscles
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Upper Limb Muscles
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Lower Limb Muscles
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Match these words with 1–4 below: head, trunk, upper limb, lower limb.
1. temporalis
2. brachioradialis
3. external oblique
4. biceps femoris
Review and Assessment
Lesson 5.4
Common Injuries and Disorders of
Muscles
Chapter 5: The Muscular System
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• strain–overstretched muscle– grade I, II, III
• contusion–bruised muscle– myositis ossificans
• cramps–spasming muscle• delayed onset muscle soreness–tear
Muscle Injuries
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• tendinitis–inflamed tendon
• tendinosis–degeneration of a tendon
Tendon Injuries
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• rotational injury at shoulder• overuse of elbow• shin splints• whiplash
Joint Injuries
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• muscular dystrophy• hernia
Muscle Disorders
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True or False?
1. Tendinitis is muscle strain.
2. A contusion is a bruise.
3. Whiplash is a joint injury.
4. A hernia is a tendon injury.
5. A strain is an over stretch of a tendon.
Review and Assessment