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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chapter 9Lecture
PowerPoint
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2401Anatomy and Physiology I
Chapter 9
Susan Gossett
sgossett@parisjc.edu
Department of Biology
Paris Junior College
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Hole’s Human Anatomyand Physiology
Twelfth Edition
Shier Butler Lewis
Chapter 9
Muscular System
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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9.1: Introduction
Three (3) Types of Muscle Tissues
• Skeletal Muscle• Usually attached to bones• Voluntary• Somatic• Striated
• Smooth Muscle• Walls of most viscera, blood vessels and skin• Involuntary• Autonomic• Not striated
• Cardiac Muscle• Wall of heart• Involuntary• Autonomic• Striated
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9.2: Structure of Skeletal Muscle
• Skeletal Muscle• Organ of the muscular system
• Skeletal muscle tissue• Nervous tissue• Blood• Connective tissues
• Fascia• Tendons• Aponeuroses
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Aponeuroses
Skeletal muscles
Tendons
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Connective Tissue Coverings
• Muscle coverings:• Epimysium• Perimysium• Endomysium
Bone
Muscle
EpimysiumPerimysium
Endomysium
Fascicle
Fascicles
Muscle fibers (cells)
Myofibrils
Thick and thin filaments
Blood vessel
Muscle fiber
Myofibril
Sarcolemma
Nucleus Filaments
Tendon
Fascia(covering muscle)
Axon of motorneuron
Sarcoplasmicreticulum
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• Muscle organ• Fascicles• Muscle cells or fibers• Myofibrils• Thick and thin myofilaments
• Actin and myosin proteins• Titin is an elastic myofilament
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Skeletal Muscle Fibers
• Sarcolemma• Sarcoplasm• Sarcoplasmic reticulum (SR)• Transverse (‘T’) tubule• Triad
• Cisternae of SR• T tubule
• Myofibril• Actin myofilaments• Myosin myofilaments• Sarcomere
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Nucleus
Mitochondria
SarcolemmaSarcoplasm
Nucleus
Myofibrils
Sarcoplasmicreticulum
Openings intotransverse tubules
Thick and thinfilaments
Cisternae ofsarcoplasmic reticulum
Transverse tubuleTriad
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9.3: Skeletal Muscle Contraction
• Movement within the myofilaments• I band (thin)• A band (thick and thin)• H zone (thick)• Z line (or disc)• M line
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Myofibril
Sarcomere
(a)
Skeletal muscle fiber
Z lineH zone M line
I band I band
(b)
Z line
Sarcoplasmicreticulum
Thick (myosin)filaments
Thin (actin)filaments
A bandA band
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Myofilaments
• Thick myofilaments • Composed of myosin protein• Form the cross-bridges
• Thin myofilaments• Composed of actin protein• Associated with troponin and tropomyosin proteins
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Cross-bridges
Actin molecule
Thin filament
Myosinmolecule
Thickfilament
Troponin Tropomyosin
Neuromuscular Junction• Also known as NMJ or myoneural junction
• Site where an axon and muscle fiber meet
• Parts• Motor neuron
• Motor end plate• Synapse
• Synaptic cleft
• Synaptic vesicles
• Neurotransmitters
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Axon branches
Mitochondria
Acetylcholine
(a)
Synapticvesicles
Synapticcleft
Foldedsarcolemma
Motorend plate
Myofibril ofmuscle fiber
Muscle fibernucleus
Motorneuron axon
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Motor Unit
• Single motor neuron• All muscle fibers controlled by motor neuron• As few as four fibers• As many as 1000’s of muscle fibers
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Motor neuronof motor unit 2
Motor neuronof motor unit 1
Skeletal musclefibers
Branches ofmotor neuronaxon
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Stimulus for Contraction
• Acetylcholine (ACh)• Nerve impulse causes release of ACh from synaptic vesicles• ACh binds to ACh receptors on motor end plate• Generates a muscle impulse• Muscle impulse eventually reaches the SR and the cisternae
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Axon branches
Mitochondria
Acetylcholine
(a)
Synapticvesicles
Synapticcleft
Foldedsarcolemma
Motorend plate
Myofibril ofmuscle fiber
Muscle fibernucleus
Motorneuron axon
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9.1 Clinical Application
Myasthenia Gravis
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Excitation-Contraction Coupling
• Muscle impulses cause SR to release calcium ions into cytosol• Calcium binds to troponin to change its shape• The position of tropomyosin is altered• Binding sites on actin are now exposed• Actin and myosin molecules bind via myosin cross-bridges
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Actin monomers
Release of Ca+2 from sarcoplasmicreticulum exposes binding sites on actin:
Muscle contraction Muscle relaxation
Active transport of Ca+2 into sarcoplasmicreticulum, which requires ATP, makesmyosin binding sites unavailable.
Ca+2 binds to troponin
Tropomyosin pulled aside
ATP
Contraction cycle
PADP +
PADP + PADP +
Ca+2
Ca+2
PADP +
PADP + PADP +
PADP
PADP
ATP ATP ATP
PADP + PADP +
ATP
Tropomyosin
Troponin Thin filament
Thick filament
Ca+2
Binding sites onactin exposed
1 Relaxed muscle
Ca+2
PADP +Ca+2
2 Exposed binding sites on actin moleculesallow the muscle contraction cycle to occur
6 ATP splits, which provides power to “cock” the myosincross-bridges
3 Cross-bridges bind actin tomyosin
5 New ATP binds to myosin, releasing linkages 4 Cross-bridges pull thin filament (power stroke), ADP and P released from myosin
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The Sliding Filament Model of Muscle Contraction
• When sarcromeres shorten, thick and thin filaments slide past one another• H zones and I bands narrow• Z lines move closer together
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Z line
(a)
Z line
Sarcomere
Contracting
Fully contracted
Relaxed
2
3
1
A band
Thinfilaments
Thickfilaments
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Cross Bridge Cycling
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Actin monomers
Release of Ca+2 from sarcoplasmicreticulum exposes binding sites on actin:
Muscle contraction Muscle relaxation
Active transport of Ca+2 into sarcoplasmicreticulum, which requires ATP, makesmyosin binding sites unavailable.
Ca+2 binds to troponin
Tropomyosin pulled aside
ATP
Contraction cycle
PADP +
PADP + PADP +
Ca+2
Ca+2
PADP +
PADP + PADP +
PADP
PADP
ATP ATP ATP
PADP + PADP +
ATP
Tropomyosin
Troponin Thin filament
Thick filament
Ca+2
Binding sites onactin exposed
1 Relaxed muscle
Ca+2
PADP +Ca+2
2 Exposed binding sites on actin moleculesallow the muscle contraction cycle to occur
6 ATP splits, which provides power to “cock” the myosincross-bridges
3 Cross-bridges bind actin tomyosin
5 New ATP binds to myosin, releasing linkages 4 Cross-bridges pull thin filament (power stroke), ADP and P released from myosin
• Myosin cross-bridge attaches to actin binding site
• Myosin cross-bridge pulls thin filament
• ADP and phosphate released from myosin
• New ATP binds to myosin
• Linkage between actin and myosin cross-bridge break
• ATP splits
• Myosin cross-bridge goes back to original position
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Relaxation
• Acetylcholinesterase – rapidly decomposes Ach remaining in the synapse
• Muscle impulse stops
• Stimulus to sarcolemma and muscle fiber membrane ceases
• Calcium moves back into sarcoplasmic reticulum (SR)
• Myosin and actin binding prevented
• Muscle fiber relaxes
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Energy Sources for Contraction
• Creatine phosphate – stores energy that quickly converts ADP to ATP
1) Creatine phosphate and 2) Cellular respiration
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ADP
ATP
ATP
P
When cellular
Creatine
Creatine
ADP
ATP
ATP
P
is high
Creatine
Creatine
When cellular is low
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Oxygen Supply and Cellular Respiration
• Cellular respiration:• Anaerobic Phase
• Glycolysis• Occurs in cytoplasm• Produces little ATP
• Aerobic Phase• Citric acid cycle• Electron transport system• Occurs in the mitochondria• Produces most ATP • Myoglobin stores extra oxygen
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ATP2Energy
Lactic acid
Glucose
ATPSynthesis of 34CO2 + H2O + Energy
Pyruvic acid
Heat
1
2
Mit
och
on
dri
aC
yto
sol
In the absence ofsufficient oxygen,glycolysis leads tolactic acidaccumulation.
Oxygen carried fromthe lungs byhemoglobin in redblood cells is storedin muscle cells bymyoglobin and isavailable to supportaerobic respiration.
Citric acidcycle
Electrontransport
chain
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Oxygen Debt
• Oxygen not available• Glycolysis continues• Pyruvic acid converted to lactic acid• Liver converts lactic acid to glucose
• Oxygen debt – amount of oxygen needed by liver cells to use the accumulated lactic acid to produce glucose
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ATP
Glucose
Glycogen
Lactic acid
Pyruvic acid
Energy tosynthesize
Energyfrom
Glycolysis andlactic acid formation(in muscle)
Synthesis of glucosefrom lactic acid(in liver)
ATP
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Muscle Fatigue
• Inability to contract muscle
• Commonly caused from:• Decreased blood flow• Ion imbalances across the sarcolemma• Accumulation of lactic acid
• Cramp – sustained, involuntary muscle contraction
• Physiological vs. psychological fatigue
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Heat Production
• By-product of cellular respiration
• Muscle cells are major source of body heat
• Blood transports heat throughout body core
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9.4: Muscular Responses
• Muscle contraction can be observed by removing a single skeletal muscle fiber and connecting it to a device that senses and records changes in the overall length of the muscle fiber.
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Threshold Stimulus
• Threshold Stimulus• Minimal strength required to cause contraction
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Recording of a Muscle Contraction
• Recording a Muscle Contraction• Twitch
• Latent period• Period of contraction• Period of relaxation
• Refractory period• All-or-none response
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Fo
rce
of
con
trac
tio
n
Time
Latentperiod
Period ofcontraction
Period ofrelaxation
Time ofstimulation
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Length-Tension RelationshipCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
(b) Overly shortened (c) Overly stretched
(a) Optimal length
Muscle fiber length
Fo
rce
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Summation
• Process by which individual twitches combine• Produces sustained contractions• Can lead to tetanic contractions
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Time(c)
(b)
Fo
rce
of
con
trac
tio
n
(a)
Fo
rce
of
con
trac
tio
nF
orc
e o
fco
ntr
acti
on
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Recruitment of Motor Units
• Recruitment - increase in the number of motor units activated
• Whole muscle composed of many motor units
• More precise movements are produced with fewer muscle fibers within a motor unit
• As intensity of stimulation increases, recruitment of motor units continues until all motor units are activated
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Sustained Contractions
• Smaller motor units (smaller diameter axons) - recruited first
• Larger motor units (larger diameter axons) - recruited later
• Produce smooth movements
• Muscle tone – continuous state of partial contraction
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Types of Contractions
• Isotonic – muscle contracts and changes length
• Concentric – shortening contraction• Eccentric – lengthening contraction
• Isometric – muscle contracts but does not change length
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Movement Movement
(a) Muscle contracts with force greater than resistance and shortens (concentric contraction)
(c) Muscle contracts but does not change length (isometric contraction)
(b) Muscle contracts with force less than resistance and lengthens (eccentric contraction)
Nomovement
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Fast Twitch and Slow Twitch Muscle Fibers
• Slow-twitch fibers (Type I)• Always oxidative• Resistant to fatigue• Red fibers • Most myoglobin• Good blood supply
• Fast-twitch glycolytic fibers (Type IIa)• White fibers (less myoglobin)• Poorer blood supply• Susceptible to fatigue
• Fast-twitch fatigue-resistant fibers (Type IIb)
• Intermediate fibers• Oxidative• Intermediate amount of myoglobin• Pink to red in color• Resistant to fatigue
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9.2 Clinical Application
Use and Disuse of Skeletal Muscles
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9.5: Smooth Muscles
• Compared to skeletal muscle fibers, smooth muscle fibers are:
• Shorter• Single, centrally located nucleus• Elongated with tapering ends• Myofilaments randomly organized• Lack striations• Lack transverse tubules• Sarcoplasmic reticula (SR) not well developed
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Smooth Muscle Fibers
• Visceral Smooth Muscle• Single-unit smooth muscle• Sheets of muscle fibers• Fibers held together by gap junctions• Exhibit rhythmicity• Exhibit peristalsis• Walls of most hollow organs
• Multi-unit Smooth Muscle• Less organized• Function as separate units • Fibers function separately• Iris of eye• Walls of blood vessels
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Smooth Muscle Contraction
• Resembles skeletal muscle contraction in that:• Interaction between actin and myosin• Both use calcium and ATP• Both are triggered by membrane impulses
• Different from skeletal muscle contraction in that:• Smooth muscle lacks troponin• Smooth muscle uses calmodulin • Two neurotransmitters affect smooth muscle
• Acetlycholine (Ach) and norepinephrine (NE)• Hormones affect smooth muscle• Stretching can trigger smooth muscle contraction• Smooth muscle slower to contract and relax• Smooth muscle more resistant to fatigue• Smooth muscle can change length without changing tautness
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9.6: Cardiac Muscle
• Located only in the heart
• Muscle fibers joined together by intercalated discs
• Fibers branch
• Network of fibers contracts as a unit
• Self-exciting and rhythmic
• Longer refractory period than skeletal muscle
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Characteristics of Muscle Tissue
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9.7: Skeletal Muscle Actions
• Skeletal muscles generate a great variety of body movements.
• The action of each muscle mostly depends upon the kind of joint it is associated with and the way the muscle is attached on either side of that joint.
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Body Movement
Four Basic Components of Levers:1. Rigid bar – bones2. Fulcrum – point on which bar moves; joint3. Object - moved against resistance; weight4. Force – supplies energy for movement; muscles
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Resistance ForceForce
Fulcrum
Resistance
Fulcrum
(a) First-class lever
FulcrumForce Force
Resistance Resistance
Fulcrum
(b) Second-class lever
Force
Resistance Force
Fulcrum(c) Third-class lever
Resistance
Fulcrum
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Levers and MovementCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Radius
Resistance
Resistance
Fulcrum
Ulna
(a)
(b)
Fulcrum
Force
Force
Forearm movement
Biceps brachiicontracting muscle
Relaxedmuscle
Triceps brachiicontracting muscle
Relaxedmuscle
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Origin and Insertion
• Origin – immovable end• Insertion – movable end
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Radius
Coracoid process
Origins ofbiceps brachii
Tendon oflong head
Tendon ofshort head
Bicepsbrachii
Insertion ofbiceps brachii
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Interaction of Skeletal Muscles
• Prime mover (agonist) – primarily responsible for movement• Synergists – assist prime mover• Antagonist – resist prime mover’s action and cause movement in the opposite direction of the prime mover• Fixators
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9.8: Major Skeletal MusclesCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Brachioradialis
Frontalis
Deltoid
Brachialis
Biceps brachii
Gracilis
Vastus medialis
Gastrocnemius
Soleus
Trapezius
Tibialis anterior
External oblique
Sartorius
Rectus femoris
Adductor longus
Vastus lateralis
Fibularis longus
Orbicularis oculiZygomaticusMasseterOrbicularis oris
Sternocleido-mastoid
Pectoralismajor
Serratusanterior
Rectusabdominis
Extensordigitorum longus
Tensorfasciaelatae
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Major Skeletal MusclesCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Gracilis
Rhomboid
Infraspinatus
Gluteus medius
Vastus lateralisSartorius
Soleus
Fibularis longus
Brachialis
Temporalis
Occipitalis
Semimembranosus
Sternocleidomastoid
Trapezius
Teres minor
Teres major
Biceps femoris
Semitendinosus
Gastrocnemius
Calcaneal tendon
Deltoid
Tricepsbrachii Latissimus
dorsiExternaloblique
Gluteusmaximus
Adductormagnus
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Muscles of Facial Expression
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Muscles of Mastication
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Muscles of Facial Expression and Mastication
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Epicranial aponeurosisFrontalis
Occipitalis
Epicranius
Masseter
Sternocleidomastoid
Temporalis
Orbicularis oculi
Zygomaticus major
Zygomaticus minor
Buccinator
Orbicularis oris
Platysma
Buccinator
Medial pterygoid
Lateral pterygoid
Temporalis
(a)
(c)(b)
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Muscles That Move the Head and Vertebral Column
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Muscles That Move the Head and Vertebral Column
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Iliocostalis lumborum
Quadratus lumborum
Spinalis thoracis
Iliocostalis thoracis
Spinalis cervicisSplenius capitis
Spinalis capitisSemispinalis capitisLongissimus capitis
Semispinalis capitis (cut)
Longissimus cervicis
Iliocostalis cervicis
Longissimus thoracis
Splenius capitis (cut)
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Muscles That Move the Pectoral Girdle
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Muscles That Move the Pectoral Girdle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Trapezius
Deltoid
Deltoid
Latissimus dorsi
Levator scapulaeSupraspinatusInfraspinatusTeres minorTeres major
Rhomboid majorRhomboid minor
(a)
(d)(c)(b)
Rhomboidminor
Rhomboidmajor
Latissimusdorsi
Trapezius
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Muscles That Move the Arm
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Muscles That Move the ArmCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Trapezius
Deltoid
Pectoralis major
External oblique
Aponeurosis of external oblique
Sternocleidomastoid
Pectoralis minor
Internal intercostal
Serratus anterior
Rectus abdominis
Internal oblique
Transversus abdominis
External intercostal
Linea alba(band of connective tissue)
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Muscles That Move the ArmCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Levator scapulae
Levator scapulae
Supraspinatus
Spine of scapula
DeltoidInfraspinatusTeres minor
Teres major
(a)
(d)(c)(b)
Supraspinatus
InfraspinatusTeres minor
Teres major
Long head oftriceps brachii
Lateral head oftriceps brachii
Tricepsbrachii
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Muscles That Move the Forearm
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Muscles That Move the Forearm
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Deltoid
Clavicle
Subscapularis
Coracobrachialis
Brachialis
Subscapularis
Coracobrachialis
Brachialis
(a)
(c) (d)(b)
Short head ofbiceps brachii
Long head ofbiceps brachii
Medial borderof scapula
Biceps brachii(short and longheads)
Trapezius
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Muscles That Move the ForearmCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Biceps brachii
Brachialis
SupinatorPronator teresBrachioradialis
Flexor carpi radialisPalmaris longusFlexor carpi ulnaris
Flexor carpi ulnaris
Pronator quadratusFlexor retinaculum
Brachioradialis
Flexor carpi radialis
Pronator teres
Pronator quadratus
(a) (b)
(c) (d) (e)
Flexor digitorumsuperficialis
Extensor carpiradialis longus
Flexor digitorumsuperficialis
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Cross Section of the ForearmCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Abductor pollicis longus m.
Flexor pollicis longus m.
Radius
Pronator teres m.
Brachioradialis m.
Radial n.
Radial a.
Flexor carpi radialis m.
Extensor digitorum m.
Ulna
Ulnar n.
Ulnar a.
Flexor carpi ulnaris m.
Median n.
Palmaris longus m.
Anterior
Plane ofsection
Extensor carpiradialis brevis m.
Extensor carpiradialis longus m.
Extensor carpiulnaris m.
Extensor pollicislongus m.
Flexor digitorumprofundus m.
Flexor digitorumsuperficialis m.
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Muscles That Move the Hand
• Flexors (anterior) and extensors (posterior)
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Muscles That Move the Hand
Triceps brachii
Flexor carpi ulnaris
Extensor carpi ulnaris
Extensor digitorum
Extensor retinaculum
Brachioradialis
Extensor carpiradialis longusand brevis
(a)
(b) (c)
Extensor carpiradialis longus
Extensor carpiradialis brevis
Extensorcarpi ulnaris
Extensordigitorum
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Muscles of the Abdominal Wall
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Muscles of the Abdominal WallCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
(a)
(b) (c) (d)
External obliqueRectus abdominis
Internal oblique
Transversus abdominis
External oblique
Internal oblique Transversusabdominis
(e)
Internal oblique
Transversusabdominis
External oblique
Linea alba
Rectus abdominis
Peritoneum
Skin
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Muscles of the Pelvic Outlet
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Muscles of Pelvic OutletCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Scrotum
IschiocavernosusClitoris
Urethral orifice
Anus
Bulbospongiosus
Levator aniGluteus maximus
Penis
Anus
Coccyx
Rectum
Urethra
Symphysis pubis
Coccygeus
Urogenital diaphragm
Levator ani
(b)(a)
(c)
Vagina
External analsphincter
Superficialtransversusperinei
Vaginal orifice
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Muscles That Move the Thigh
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Muscles That Move the Thigh
Psoas major
Psoas minorIliacus
Rectus femoris
Sartorius
Sartorius
Vastus lateralis Vastus intermedius
Patella
Adductor longus
Pectineus
Adductormagnus
GracilisVastus medialis
Gracilis
Adductor brevis Adductor longus
Adductor magnus
IliacusPsoas majorPsoas minor
(a) (b)
(c) (d) (e)
(f) (g)
Tensor fasciae latae
Quadriceps femoristendon (patellar tendon)
Patellarligament
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Muscles That Move the Thigh
Gluteus medius
Gluteus medius
Gluteus maximus
Gluteus maximus
Biceps femorisIliotibial tract (band)
Vastus lateralis
Rectus femoris
Sartorius
Tensor fasciae latae
Gluteus minimusPiriformis
(a)
(b) (c) (d)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Muscles That Move the Leg
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Muscles That Move the Leg
Adductor magnus
Gracilis
Semitendinosus
Semimembranosus
Semimembranosus
Sartorius
Gastrocnemius
Gluteus medius
Gluteus maximus
Biceps femoris
Semitendinosus
(a)
(b) (c)
Vastus lateraliscovered by fascia
Biceps femoris(short head)
Biceps femoris(long head)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Muscles That Move the Leg
Gracilis m.
Semimembranosus m.Semitendinosus m.
Sartorius m.Vastus medialis m.
Rectus femoris m.Adipose tissue
Skin
Adductor magnus m.
Adductor longus m.Great saphenousv.Femoralv . and a.
Vastus intermedius m.
Shaft of femur
Sciatic n.
Vastus lateralis m.
Lateral Medial
Anterior
Long head ofbiceps femoris m.
Short head ofbiceps femoris m.
Planeofsection
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Muscles That Move the LegCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Semitendinosus
SemimembranosusGracilisSartorius
Gastrocnemius:
Medial headLateral head
Soleus
Calcaneal tendon
Flexor retinaculum
Calcaneus
Biceps femoris
Plantaris
Soleus
Gastrocnemius
(a)
(b) (c)
(d) (e)
Flexor digitorumlongus
Fibularretinacula
Fibularisbrevis
Fibularislongus
Iliotibial tract(band)
Flexor digitorumlongus
Tibialis posterior
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Muscles That Move the Foot
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Muscles That Move the FootCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fibularis longus
Fibularis brevis
Fibularis tertius
Patella
Patellar ligament
Gastrocnemius
Soleus
Extensor retinacula
(a)
(b) (c) (d)
Tibia
Tibialis anterior
Extensor digitorumlongus
Extensor digitorumlongus
Tibialis anterior
Extensorhallucislongus
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Muscles That Move the FootCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Biceps femoris
Gastrocnemius
SoleusFibularis longus
Fibularis longus
Calcaneal tendon
Head of fibula
Fibularis tertiusFibularis brevis Extensor retinacula
Fibularis brevis
(a)
(b) (c)
Vastus lateralis
Tibialis anterior
Extensor digitorumlongus
Fibularretinacula
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9.3 Clinical Application
TMJ Syndrome
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9.9: Lifespan Changes
• Myoglobin, ATP, and creatine phosphate decline
• By age 80, half of muscle mass has atrophied
• Adipose cells and connective tissues replace muscle tissue
• Exercise helps to maintain muscle mass and function
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Important Points in Chapter 9:Outcomes to be Assessed
9.1: Introduction
List various outcomes of muscle action.
9.2: Structure of a Skeletal Muscle
Describe how connective tissue is a part of the structure of a skeletal muscle.
Name the major parts of a skeletal muscle fiber and describe the functions of each.
9.3: Skeletal Muscle Contraction
Describe the neural control of skeletal muscle contraction.
Identify the major events that occur during skeletal muscle fiber contraction.
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Important Points in Chapter 9:Outcomes to be Assessed
List the energy sources for skeletal muscle fiber contraction.
Describe how a muscle may become fatigued.
Describe oxygen debt.
9.4: Muscular Responses
Distinguish between fast and slow twitch muscle fibers.
Distinguish between a twitch and a sustained contraction.
Describe how exercise affects skeletal muscles.
Explain how various types of muscular contractions produce body movements and help maintain posture.
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Important Points in Chapter 9:Outcomes to be Assessed
9.5: Smooth Muscle
Distinguish between the structures and functions of multiunit smooth muscle and visceral smooth muscle.
Compare the contraction mechanisms of skeletal and smooth muscle fibers.
9.6: Cardiac Muscle
Compare the contraction mechanisms of skeletal and cardiac muscle fibers.
9.7: Skeletal Muscle Actions
Explain how the attachments, locations, and interactions of skeletal muscles make possible certain movements.
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Important Points in Chapter 9:Outcomes to be Assessed
9.8: Major Skeletal Muscles
Identify and locate the skeletal muscles of each body region and describe the action (s) of each muscle.
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Quiz 9
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Read Chapter 10.