ch 9

  1. endomysium
    • wraps a muscle fiber,
    • areolar ct
  2. perimysium
    • wrapped fascicles
    • collagen sheath
  3. epimysium
    • wraps entire muscle
    • dense fibrous ct
  4. excitability
    able to receive and respond to stimuli
  5. contractility
    shorten when a stimulus is adequate
  6. extensibility
    ability to be stretched
  7. elasticity
    return to original length
  8. functions of muscle
    • motion
    • positive maintenance
    • joint stabilizatin
    • heat production
  9. indirect attachment to bones
    • tendon- extension of fascia
    • aponeurosis- flat sheet like
  10. muscle fiber
    muscle cell
  11. sarcolema
    plasma membrane
  12. sarcoplasm
  13. sarcoplasmic reticulum
    true smooth er
  14. myoglobin
    o2 storage pigment in muscle
  15. myofibrils
    make up muscle fibers, run lenth of cell parallel
  16. myofilaments
    make up myofibrils do not run length of cell. myosin or actin- compartments are called sarcomeres
  17. sarcomere
    functional unit of contraction
  18. thick filamen
    • bundles of myosin molecules
    • has actin binding sites of its globular head
    • has atp binding site
  19. thin filament
    • actin molecules
    • has myosin binding sites
    • associated with two regulatory proteins
  20. tropomyosin
    • spirals around the actin filament, covering & blocking myosin binding sites
    • preventing contraction
  21. troponin
    • holds tropomyosin in place around actin;
    • has Ca binding sites
  22. a band
    length of thick filaments
  23. H zone
    central narrow area of thick filaments
  24. M line
    fine threads in the H-zone; connects adjacent thick filaments
  25. I band
    light appearing area on either side of the A band; mostly thin myofilaments
  26. Z disk
    sarcomere boder
  27. sliding filament theory
  28. pre stimulus
    resting, negatively charged, polarized
  29. neuromuscular action
    • ach released
    • binds to receptors is sarcolemma
    • ach causes Ca open
    • Ca rushes into sarcoplasm
    • Ca binding exposes actin
    • power stroke
  30. energy for working stroke
    atp attached to myosin is split by ATPase
  31. acetylcholinesterase
    enzyme that stops nerve impulse
  32. events at muscular junction
    • action potential arrives
    • Ca channels in neuron open
    • ACH is released from neuron by exocytosis
    • ACH binds to receptors, opens channels
    • ACHE terminates activity
  33. motor unit
    single motor neuron and number of musclefibers stimulated by it
  34. small motor unit
    • 1 neuron 2-10 muscle fibers
    • precise muscle movements
  35. large motor unit
    • 1 neuron + 500 - 2000 muscle fibers
    • gross motor movements like leg
  36. average motor unit
    150 muscle fibers and neuron
  37. basic fuel for muscle
    • atp
    • comes from phosphocreatine stored in muscle tissue
  38. atp used rapidly
    phosphocreatine 15-30 sec
    glycogen (several min)
    fats long time
  39. threshold strength
    weakest stimulus to elicit contraction
  40. all or none principal
    each fiber will be contracted or not
  41. muscle twitch
    rapid jerky response to stimulus
  42. refractory period
    time during contraction when muscle fiber is not able to be further stimulated
  43. tetanus
    complete muscle contraction
  44. lock jaw
    caused by clostridium tetani
  45. treppe
    • stimulation/contraction/relaxation
    • 2nd stimulus will result in stronger contraction
  46. isotoni
    equal movement muscle
  47. concentric
  48. eccentric
  49. isometric
    muscle lenght is constant but tension increases
Card Set
ch 9
muscle tissue