ana 4

  1. acetyl cholinesterase
    enzyme that breaks down acetycholine not permeable to Na+(sodium) but now it is permeable to K+(potassium)
  2. repolarized
    • returns to the resting potential
    • impulse move along the cell membrane down the T-tubule
    • to the sarcoplasmic reticulim
  3. last step of muscle contraction
    when the impulse gets to the reticulum is causes calcium ions which have been stored there to be released to the cytoplasm

    • then the calcium binds to the troponin which causes the tropomyosin to shift and expose the binding myosin
    • this binds the sites on the actin to the actin and will pull the actin filaments inward
  4. oxygen debt
    the amount of oxygen that needs to be paid back
  5. all or none principle
    an individual muscle fiber will contract to its fullest extent or not at all
  6. Stimulus
    any force that affects the excitability of a muscle or a nerve
  7. threshold or minimal
    the weakest stimulus that can excite  a muscle to contract
  8. subthreshold or subminimal
    will not initial contraction
  9. Maximal
    a stimulus that excites all the motor units of the muscle
  10. refractory period
    • time after a stimulus during which a 2nd stimulus will not cause a contraction
    • repolarization has to not occur
  11. myogram
    a record of a muscle contraction
  12. latent period
    between the application of the stimulus and the beginning of the contraction
  13. contraction
    shortening muscle
  14. relaxation period
    muscle is lengthening
  15. tetanus
    when 2 stimuli are applied and the 2nd is delayed until the refractory period is over

    skeletal muscle will respond to both stimuli

    if 2nd stimuli is applied after refractory but before it finishes refracting it will be stronger than the 1st
  16. wave summation
    the increased strength of the contraction

    results when the stimuli id followed in rapid succession
  17. tetanus
    a sustained forceful contraction without relaxation resulting from a series of stimuli on the rapid succession
  18. muscle tone
    the continual level of some degree of contraction of a muscle
  19. Treppe
    condition in which a muscle contracts more forcefully after its contracted several times
  20. isotonic
    action in which the muscle tone or tension remains the same but the length changes movement
  21. isometric
    the tension changes but the length does not move "no movement"
  22. Cardiac muscle
    • only in the heart
    • striated, branched, involuntary
    • differences
    • 1.intercalated discs
    • transverse thinking of the sarcolemma where the fibers connect
    • low electrical resistance and impulse can be conducted from the cell
    • 2. times of contraction
    • 3.source of stimulation
  23. smooth muscle
    • non-striated, cells are spindle shaped with a single nucleus
    • ex. walls of the stomach
    • blood vessels
    • still contain actin and myosin but not as orderly arranges

Card Set
ana 4
muscular system