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Chapter 9 - Muscular System         Three Types of Muscle TissuesSkeletal Muscle                           Cardiac Muscle ...
Structure of a Skeletal                    MuscleSkeletal Muscle   • organ of the muscular   system   • skeletal muscle ti...
Structure of a Skeletal                  Muscle• epimysium• perimysium• fascicle• endomysium• muscle• fascicles• muscle fi...
Skeletal Muscle Fiber• sarcolemma• sacroplasm• sarcoplasmic reticulum• transverse tubule• triad    • cisterna of sarcoplas...
Structure of a Skeletal        Muscle
Sarcomere• I band• A band• H zone• Z line• M line
Myofilaments                           Thin FilamentsThick Filaments                               • composed of actin    ...
Neuromuscular Junction• site where axon andmuscle fibercommunicate• motor neuron• motor end plate• synaptic cleft• synapti...
Motor Unit• single motor neuron• all muscle fibers controlled by motor neuron
Stimulus for Contraction• acetylcholine (ACh)• nerve impulse causes releaseof acetylcholine from synapticvesicles• binds t...
Excitation Contraction                 Coupling• muscle impulses causesarcoplasmic reticulum torelease calcium ions intocy...
Sliding Filament Theory• When sarcromeresshorten, thick and thinfilaments slide past oneanother• H zones and I bandsget na...
Cross-bridge Cycling• actin and myosincross-bridge bind• myosin cross-bridge pulls actin•ADP and phosphatereleased from my...
Relaxation• acetylcholinesterase – breaks down acetylcholine• muscle impulse stops• calcium moves back into sarcoplasmic r...
Energy Sources for              Contraction    1) Creatine phosphate       2) Cellular respiration• creatine phosphate – s...
Oxygen Supply and             Cellular Respiration• Anaerobic Phase   • glycolysis   • produces little ATP• Aerobic Phase ...
Oxygen DebtOxygen debt – amount of oxygen needed by liver to convertlactic acid to glucose• oxygen not available• glycolys...
Muscle Fatigue• inability to contract• commonly caused from    • decreased blood flow    • ion imbalances    • accumulatio...
Heat Production• by-product  of cellular respiration• muscle cells are major source of body heat• blood transports heat th...
Muscular ResponsesThreshold Stimulus   • minimal strength required to cause contractionRecording a MuscleContraction   • t...
Summation• process by which individual twitches combine• produces sustained contractions• can lead to tetanic contractions
Recruitment of Motor Units• recruitment - increase in the number of motor unitsactivated• whole muscle composed of many mo...
Sustained Contractions• smaller motor units recruited first• larger motor units recruited later• produces smooth movements...
Types of Contractions• isotonic – muscle contracts and   • concentric – shortening contractionchanges length              ...
Fast and Slow Twitch                Muscle FibersSlow-twitch fibers (type I)               Fast-twitch fatigue-    • alway...
Smooth Muscle FibersCompared to skeletal muscle fibers  • shorter  • single nucleus  • elongated with tapering ends  • myo...
Types of Smooth MuscleVisceral Smooth Muscle         Multiunit Smooth Muscle   • single-unit smooth          • fibers func...
Smooth Muscle              Contraction• Resembles skeletal muscle contraction   • interaction between actin and myosin   •...
Cardiac Muscle• only in the heart• muscle fibers joined together by intercalated discs• fibers branch• network of fibers c...
Skeletal Muscle Actions• origin – immovable end• insertion – movable end• prime mover (agonist) –primarily responsible for...
Major Skeletal Muscles
Major Skeletal Muscles
Muscles of Facial  Expression
Muscles of Mastication
Muscles of Facial Expression and   Mastication
Muscles That Move the Head and Vertebral       Column
Muscles That Move the   Pectoral Girdle
Muscles That Move the         Arm
Deep Muscles of the  Back and Neck                      9-39
Muscles of theShoulder and Back
Muscles of the AnteriorChest and Abdominal Wall
Muscles That Move the      Forearm
Muscles That Move the        Hand
Muscles of theShoulder and Arm
Cross Section of the       Arm
Muscles of theShoulder and Arm
Muscles of theArm and Forearm
Muscles of theArm and Forearm
Cross Section of the     Forearm
Muscles of the Abdominal          Wall
Muscles of the Abdominal          Wall
Muscles of the Pelvic       Outlet
Muscles of Pelvic Outletsand Urogenital Diaphragm                        9-53
Muscles That Move the        Thigh
Muscles That Move the         Leg
Muscles That Move the        Foot
Muscles of the Thigh and          Leg                       9-57
Muscles of the Thigh and Leg                         9-58
Muscles of the Thigh and          Leg
Cross Section of the Thigh
Muscles of the Leg
Muscles of the Leg
Muscles of the Leg                     9-63
Cross Section of the       Leg
Life-Span Changes• myoglobin, ATP, and creatinephosphate decline• by age 80, half of muscle masshas atrophied• adipose cel...
Clinical Application              Myasthenia Gravis• autoimmune disorder• receptors for acetylcholine on muscle cells are ...
Active vs. Inactive Muscle:     Muscular Atrophy
Exercise and Diet Stimulates          Muscle DevelopmentArnold Schwarzenegger – Body Builder, Actor, and Politician       ...
Chapter 9   muscular system
Chapter 9   muscular system
Chapter 9   muscular system
Chapter 9   muscular system
Chapter 9   muscular system
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Chapter 9 muscular system

  1. 1. Chapter 9 - Muscular System Three Types of Muscle TissuesSkeletal Muscle Cardiac Muscle • usually • wall of heart attached to • not under Smooth Muscle bones conscious • walls of most viscera, • under control blood vessels, skin conscious • striated • not under conscious control control • striated • not striated
  2. 2. Structure of a Skeletal MuscleSkeletal Muscle • organ of the muscular system • skeletal muscle tissue • nervous tissue • blood • connective tissues • fascia • tendon • aponeuroses
  3. 3. Structure of a Skeletal Muscle• epimysium• perimysium• fascicle• endomysium• muscle• fascicles• muscle fibers• myofibrils• thick and thin filaments
  4. 4. Skeletal Muscle Fiber• sarcolemma• sacroplasm• sarcoplasmic reticulum• transverse tubule• triad • cisterna of sarcoplasmic reticulum • transverse tubule• myofibril• actin filaments• myosin filaments• sarcomere
  5. 5. Structure of a Skeletal Muscle
  6. 6. Sarcomere• I band• A band• H zone• Z line• M line
  7. 7. Myofilaments Thin FilamentsThick Filaments • composed of actin • composed of myosin • associated with troponin • cross-bridges and tropomyosin
  8. 8. Neuromuscular Junction• site where axon andmuscle fibercommunicate• motor neuron• motor end plate• synaptic cleft• synaptic vesicles• neurotransmitters
  9. 9. Motor Unit• single motor neuron• all muscle fibers controlled by motor neuron
  10. 10. Stimulus for Contraction• acetylcholine (ACh)• nerve impulse causes releaseof acetylcholine from synapticvesicles• binds to acetylcholinereceptors on motor end plate• generates a muscle impulse• muscle impulse eventuallyreaches sarcoplasmicreticulum
  11. 11. Excitation Contraction Coupling• muscle impulses causesarcoplasmic reticulum torelease calcium ions intocytosol• calcium binds to troponin tochange its shape• position of tropomyosin isaltered• binding sites on actinexposed• actin and myosin bind 9-11
  12. 12. Sliding Filament Theory• When sarcromeresshorten, thick and thinfilaments slide past oneanother• H zones and I bandsget narrower• Z lines move closertogether
  13. 13. Cross-bridge Cycling• actin and myosincross-bridge bind• myosin cross-bridge pulls actin•ADP and phosphatereleased from myosin• new ATP binds tomyosin• linkage between actinand myosin cross-bridgebreak •ATP splits•myosin cross-bridge goes backto original position
  14. 14. Relaxation• acetylcholinesterase – breaks down acetylcholine• muscle impulse stops• calcium moves back into sarcoplasmic reticulum• myosin and actin binding prevented
  15. 15. Energy Sources for Contraction 1) Creatine phosphate 2) Cellular respiration• creatine phosphate – stores energy that quickly convertsADP to ATP
  16. 16. Oxygen Supply and Cellular Respiration• Anaerobic Phase • glycolysis • produces little ATP• Aerobic Phase • citric acid cycle • electron transport chain • produces most ATP • myoglobin stores extra oxygen
  17. 17. Oxygen DebtOxygen debt – amount of oxygen needed by liver to convertlactic acid to glucose• oxygen not available• glycolysis continues• pyruvic acidconverted to lactic acid• liver converts lacticacid to glucose
  18. 18. Muscle Fatigue• inability to contract• commonly caused from • decreased blood flow • ion imbalances • accumulation of lactic acid• cramp – sustained, involuntary contraction
  19. 19. Heat Production• by-product of cellular respiration• muscle cells are major source of body heat• blood transports heat throughout body
  20. 20. Muscular ResponsesThreshold Stimulus • minimal strength required to cause contractionRecording a MuscleContraction • twitch • latent period • period of contraction • period of relaxation • refractory period • all-or-none response
  21. 21. Summation• process by which individual twitches combine• produces sustained contractions• can lead to tetanic contractions
  22. 22. Recruitment of Motor Units• recruitment - increase in the number of motor unitsactivated• whole muscle composed of many motor units• as intensity of stimulation increases, recruitment ofmotor units continues until all motor units areactivated
  23. 23. Sustained Contractions• smaller motor units recruited first• larger motor units recruited later• produces smooth movements• muscle tone – continuous state of partial contraction
  24. 24. Types of Contractions• isotonic – muscle contracts and • concentric – shortening contractionchanges length • isometric – muscle contracts but• eccentric – lengthening does not change lengthcontraction
  25. 25. Fast and Slow Twitch Muscle FibersSlow-twitch fibers (type I) Fast-twitch fatigue- • always oxidative resistant fibers (type • resistant to fatigue IIb) • red fibers • intermediate fibers • most myoglobin • oxidative • good blood supply • intermediate amount ofFast-twitch glycolytic fibers (type II) myoglobin • white fibers (less myoglobin) • pink to red in color • poorer blood supply • susceptible to fatigue
  26. 26. Smooth Muscle FibersCompared to skeletal muscle fibers • shorter • single nucleus • elongated with tapering ends • myofilaments randomly organized • no striations • lack transverse tubules • sarcoplasmic reticula not well developed
  27. 27. Types of Smooth MuscleVisceral Smooth Muscle Multiunit Smooth Muscle • single-unit smooth • fibers function separately muscle • irises of eye • sheets of muscle fibers • walls of blood vessels • fibers held together by gap junctions • exhibit rhythmicity • exhibit peristalsis • walls of most hollow organs
  28. 28. Smooth Muscle Contraction• Resembles skeletal muscle contraction • interaction between actin and myosin • both use calcium and ATP • both depend on impulses• Different from skeletal muscle contraction • smooth muscle lacks troponin • smooth muscle depends on calmodulin • two neurotransmitters affect smooth muscle • acetlycholine and norepinephrine • hormones affect smooth muscle • stretching can trigger smooth muscle contraction • smooth muscle slower to contract and relax • smooth muscle more resistant to fatigue
  29. 29. Cardiac Muscle• 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
  30. 30. Skeletal Muscle Actions• origin – immovable end• insertion – movable end• prime mover (agonist) –primarily responsible formovement• synergists – assist primemover• antagonist – resist primemover’s action and causemovement in the oppositedirection 9-30
  31. 31. Major Skeletal Muscles
  32. 32. Major Skeletal Muscles
  33. 33. Muscles of Facial Expression
  34. 34. Muscles of Mastication
  35. 35. Muscles of Facial Expression and Mastication
  36. 36. Muscles That Move the Head and Vertebral Column
  37. 37. Muscles That Move the Pectoral Girdle
  38. 38. Muscles That Move the Arm
  39. 39. Deep Muscles of the Back and Neck 9-39
  40. 40. Muscles of theShoulder and Back
  41. 41. Muscles of the AnteriorChest and Abdominal Wall
  42. 42. Muscles That Move the Forearm
  43. 43. Muscles That Move the Hand
  44. 44. Muscles of theShoulder and Arm
  45. 45. Cross Section of the Arm
  46. 46. Muscles of theShoulder and Arm
  47. 47. Muscles of theArm and Forearm
  48. 48. Muscles of theArm and Forearm
  49. 49. Cross Section of the Forearm
  50. 50. Muscles of the Abdominal Wall
  51. 51. Muscles of the Abdominal Wall
  52. 52. Muscles of the Pelvic Outlet
  53. 53. Muscles of Pelvic Outletsand Urogenital Diaphragm 9-53
  54. 54. Muscles That Move the Thigh
  55. 55. Muscles That Move the Leg
  56. 56. Muscles That Move the Foot
  57. 57. Muscles of the Thigh and Leg 9-57
  58. 58. Muscles of the Thigh and Leg 9-58
  59. 59. Muscles of the Thigh and Leg
  60. 60. Cross Section of the Thigh
  61. 61. Muscles of the Leg
  62. 62. Muscles of the Leg
  63. 63. Muscles of the Leg 9-63
  64. 64. Cross Section of the Leg
  65. 65. Life-Span Changes• myoglobin, ATP, and creatinephosphate decline• by age 80, half of muscle masshas atrophied• adipose cells and connectivetissues replace muscle tissue• exercise helps to maintainmuscle mass and function
  66. 66. Clinical Application Myasthenia Gravis• autoimmune disorder• receptors for acetylcholine on muscle cells are attacked• weak and easily fatigued muscles result• difficulty swallowing and chewing• ventilator needed if respiratory muscles are affected• treatments include • drugs that boost acetylcholine • removing thymus gland • immunosuppressant drugs • antibodies
  67. 67. Active vs. Inactive Muscle: Muscular Atrophy
  68. 68. Exercise and Diet Stimulates Muscle DevelopmentArnold Schwarzenegger – Body Builder, Actor, and Politician Hans and Franz

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