chapter 9 Muscular system

  1. Name the three types of muscle tissue?
    • Skeletal
    • Smooth
    • Cardiac
  2. What is the definition of skeletal muscle tissue?
    Pulls on bones
  3. Define smooth muscle tissue?
    • Pushes fluids, & solids
    • Rythmic
  4. Define cardic muscle tissue?
    Pushes blood
  5. Name the four characteristics of all muscle tissue?
    • Contractibility
    • Excitability
    • Extensibility
    • Elasticity
  6. What is contractibilty?
    Primary function
  7. What is purpose of excitability?
    Respond to a stimulus
  8. What is the purpose of extensibility?
    • Extend beyond its original
    • Lenght & still contract
  9. What is the purpose of elasticity?
    Rebound to its original length
  10. How many skeletal muscles are there?
    Over 700
  11. Each muscle is what type of tissue?
    An organ
  12. What type of muscles are skeletal?
  13. Name the functions of skeletal muscles?
    • Produce skeletal movement by pulling on muscles
    • Maintain body posture, tension continual in some muscles
    • Support soft tissue, abdominal wall
    • Guard orifices, voluntary control over swallowing, defection, urination
    • Heat production, homeostasis (body temp.)
  14. Define muscle fiber?
    A long cylindrical "cell"
  15. How long are huge fused "cells"?
    16 inches
  16. Name the three connective tissue wrappings of the skeletal muscles?
    • Endomysium
    • Perimysium
    • Epimysium
  17. What are muscle fibers arranged into?
  18. Where is endomysium?
    Around single muscle fiber
  19. Where is perimysium?
    Around a fascicle (bundle) of fibers
  20. Where is epimysium found?
    Covers the entire skeletal muscle.
  21. What function does the epimysium serve? What is it made of?
    • Overcoat
    • Dense irregular tissue
    • Blood vessels & nerves
    • Epimysium continous with tendon
  22. What is the funciton of perimysium? What is it made of?
    • Divides muscle into compartments called fascicles
    • Blood vessels & nerves; collagen &
    • Elastic fibers
  23. What is the function of the endomysium? What is it made of?
    • Surrounds each muscle fiber (fused cells)
    • Delicate network with capillaries;
    • Recticular fibers
    • Myosatellite cells
  24. What is aponeuroses?
    Flat broad tendons
  25. What are characteristics of connective tissue sheaths?
    • Endomysium and perimysium are interwoven
    • All sheaths continous with muscle tendon &
    • Aponeuroses. Take force of contraction
    • To bone, muscle or skin
  26. What is muscle fiber? Name some characteristics.
    • Muscle fiber is formed during development
    • From the fusion of several undifferentiated
    • Immature cells known as myoblasts into long,
    • Cylindrical, multi-nucleanated cells.
  27. What are myofibrils?
    • Cylindrical organelles found within
    • Muscle cells
  28. What is the sarcolemma?
    • Plasma membrane of a muscle cell
    • Invaginates into the cytoplasm of the muscle cell,
    • Forming membranous tubules called
    • Transverse tubules (T-tubules).
  29. What is the scaroplasma? What does it contain?
    • The cytoplasm of the muscle cell
    • Myofibrils with myofilaments (protein fibers)
    • Multinucleated (pushed to cell membrane)
    • Mitochondria (more than any other cells of the body)
  30. What is the sarcoplasmic reticulum? Where is it located? What else about it is important?
    • Corresponds to smooth endoplasmic reticulum
    • Sits as a sleeve around myofibrils
    • Has terminal cisternae which holds
    • And releases Ca++ ions
  31. What fills the myofibril?
  32. Beginning with skeletal muscle what is the are next layers contained?
    • Skeletal muscle contains muscle fascicle
    • Muscle fascicle contains muscle fibers
    • Muscle fiber contains myofibrils
    • Myofibrils surrounded by sarcoplasmic
    • Reticulum consits of sacromeres
    • Contains thin and thick filaments
  33. What is actin?
    Thin strands of protein
  34. What is myosin?
    Thick filaments of protein
  35. Define sacromere.
    • Bundle of thin and thick filaments
    • Repeating units formed of actin
    • And myosin
  36. Which area of the muscle cell does the actual contracting?
    • Sarcomere
    • Contracts to 1/3 of
    • Length
  37. How many sacromeres/myofibrils are there?
    10,000 linearly arranged
  38. On a microscopic slide of muscle what is indicated by the light and dark bands?
    • Zones of actin
    • & Myosin overlap
  39. What is the length of a relaxed sacromere?
    • From z line to
    • Z line
  40. What is muscle contraction?
    • Muscle fiber shorten in length (exerts a pull)
    • Result of interatcions between action &
    • Myosin filaments
    • (Sliding filament theory)
  41. What has been observed about the sliding filament theory (of muscle contraction)?
    • The H band & I band
    • Get smaller the Z lines
    • Get closer together
  42. When we use the word bands to describe the lines of myosin and actin filaments what is meant? Why?
    • They are actually discs
    • As the structure is cylindrical
  43. Describe the sliding filament theory.
    • Myosin heads attache to actin & pull
    • It toward the M line myosin head is
    • The crossbridge myosin head binds,
    • Pulls, detaches, re-sets, repeats
    • Sarcomere shortens
  44. When muscles contract what is the ration of myosin to actin?
    3 myosin to 1 actin filament
  45. What is tropomyosin molecules?
    • An actin binding protein that forms
    • A long chain that covers the active sites
    • Preventing actin-myosin interaction
  46. What is function of troponin?
    Holds the tropomyosin in place
  47. What does sarkos mean?
  48. What does lemma mean?
  49. What happens in the zone of over lap?
    • The thin filaments pass between
    • The thick filaments
  50. What is the triad area?
    • Combination of the terminal cisternae
    • & trasverse tubules
  51. What does the A band contain?
    Area containing thick filaments
  52. What is region from the Z line to the A band?
    • I band
    • Which contains thin filaments
  53. What does the amount of tension depend on?
    • Number of cross bridge
    • Interactions that occur
    • In the sarcomeres
    • Individual structure
  54. When does contraction stop?
    • When Ca++ are returned &
    • Stored in sacroplasmic reticulum
    • Uses ATP
  55. What does myosin need to detach from actin during contraction? What position does it return to?
    • Require ATP and returns
    • To "cocked" position
  56. Define Rigor Mortis
    • Circulation ceases with death
    • Skeletal muscles can not produce ATP without oxygen
    • Fiber can not recapture Ca++ to SR, contraction continues
    • No ATP to release myosin head from actin filament
    • Muscle locks in contracted position
    • "stiff as a board" lasts 15-20 hrs.
    • Tell time of death
  57. What is each muscle controlled by?
    A motor neuron
  58. What is each muslce fiber controlled by?
    A motor neuron
  59. Where can a motor neuron's cell body by found?
    In the spinal cord
  60. What do a motor neuron and muscle fiber make up?
    Neuromuscular junction
  61. What is the axon? Where is it located?
    • Long process of the motor neuron
    • Extends to the fiber
  62. What is the motor end plate and synaptic terminal separated by?
    Synaptic cleft
  63. What is the synaptic terminal?
    • The expanded tip of the axon
    • At the neuromuscular synapse
  64. Where is the ACh (acetylcholine) released?
    • At the synaptic terminal
    • Of the nerve
  65. What is the action potential?
    • An electrical impulse (excitibilty) that sweeps over
    • The suface of the sarcolemma
    • & into each T tubule
  66. What generates the action potential?
    • ACh is released into the synaptic cleft
    • The ACh released then binds to receptor sites
    • On the motor end plate, initiating a change in the
    • Local transmembrane potential.
  67. What is the result of the action potential?
  68. What enzyme breaks down the ACh molecules?
    • AChE
    • Acetylcholinesterase
  69. Define the motor unit?
    • All of the muslce fibers
    • Controlled by a single motor neuron
  70. Where are small motor units found? What is there function?
    • Found in fingers
    • For fine control
  71. What is fine control defined as?
    • Fewer fibers controlled by one
    • Neuron
  72. What does all or nothing mean?
    • Each fiber contracts completely
    • Or not at all
  73. What does the amount of tension depend on?
    • Frequency of stimulation
    • Number of motor units involved
  74. What gives the precise control of muscle tension?
    Nervous system
  75. Define muscle twitch?
    A single momentary contraction
  76. How is the amount of force determined?
    • Depends of how many motor units
    • Are activated (recruitment)
  77. Within a muscle are bundles of muscle fibers called what?
  78. How do muscle fibers arrange themselves within the fascicle?
    They lie paralle to one another
  79. What are the four basic types of fascicle arrangements? What do they affect?
    • Parallel
    • Pennate
    • Convergent
    • Circular
    • Power, range, & speed
  80. What is defined as a parallel muscle?
    • Fibers run the length of the muscle
    • (maximum shortening 1/3 of length)
  81. What type of muscle are most muscles in the body?
  82. What is the shape of parallel muscles?
    Strap-like or spindle shaped
  83. Define convergent muscles?
    • Muscles having a broad origin;
    • Fibers converge on a single insertion from
    • Multiple directions
  84. What is the shape of convergent muscles?
    Triangle or fan-shaped
  85. Define versatile? What muscle type is versatile?
    • Direction of pull can be changed
    • Convergent
  86. Define pennate muscles.
    • Short fibers attach at oblique angles to a central
    • Tendon
  87. What muscle types are the most powerful & have more tension?
  88. What is unipennate?
    All fibers on the same side of the tendon
  89. What is bipennate?
    Muscle fibers on both sides of the tendon
  90. What is multipennate?
    Tendon branches within the muscle
  91. Define circular muscles?
    • Concentric rings around external body openings
    • Usually sphincters or valves
  92. What do circular muscles guard?
    Entrances/exits by contracting
  93. What is the minimum of points that every skeletal muscle is attached to bone or connective tissue?
    • Two points
    • If it's from bone-bone
    • Always crosses articulation
  94. Where is the muscles origin attached to?
    To the immovable bone
  95. Where does a muscle begin?
    At an origin
  96. Where does a muscle end?
    At the insertion
  97. Where is the insertion attached to?
    The movable bone
  98. How does action occur?
    As the insertion moves towards its origin
  99. Name the three primary actions?
    • Prime movers (Agonists)
    • Synergists
    • Antagonists
  100. Define Agonists? Give examples.
    • Cheifly responsible for producing a
    • Particular movement
    • Flexion at the elbow
  101. Define Synergists?
    • Contracts, it assists the prime mover in
    • Performing that action
    • Provide additonal pull near the insertion
    • Or stabilize the point of origin
  102. Give an example of a synergist.
    • Latissimus dorsi assisted by
    • Teres major pull the arm inferiorly
  103. Define antagonist? Give example.
    • Oppose the action of the agonist (prime mover)
    • If the agonist produces flexion, the antagonist
    • Will produce extension
  104. What are fixators?
    • Synergists that assist an agonist by preventing
    • Movement at a joint and thereby stablizing
    • The origin of the agonist.
  105. What is idea behind the principal of levers?
    • Skeletal muscles do not work in isolation
    • Muscles working with bone
    • Simple machines make it easier to do work (with bone)
  106. Name the simple machines?
    • Ramp
    • Pulley
    • Wheels
    • Lever
  107. Define lever? Name the parts of the body that correspond to lever system.
    • A rigid bar (bones) that moves on a fulcrum (joint)
    • (Fixed point) when a force (effort) (muscle contraction)
    • Is applied to it to move a resistance (load)
  108. What is the first class lever? Give example.
    • See saw
    • They are rare in the body
    • Occipital condyle & C1
  109. What is the second class lever? Give example
    • Wheel barrow
    • Force is magnified
    • Resistance covers a shorter distance & is slower
    • Uncommon
    • Plantar flexion
  110. How common are the third class levers in the body? Name the characteristic of this type. Give examples
    • Most skeletal muscle of the body
    • Speed and distance increased at the expense of force
    • Biceps brachii
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chapter 9 Muscular system
Muscular system