A&P Lab Test 3 (1)

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  1. Stimulus must reach threshold potential in order for AP to occur. Individual muscle fiber is stimulated to depolarization, AP is propagated along sarcolemma, it must contract to its full force, it can't partially contract.
    All or nothing principle
  2. If a stimulus depolarizes a neuron to threshold, the neuron fires at its maximum voltage (all); if threshold is not reached, the neuron does not fire at all (none). Given above threshold, stronger stimuli do not produce stronger action potentials.
    All or nothing principle
  3. the brief contraction of all muscle fibers in a motor unit in response to a single action potential in its motor neuron.
  4. includes a somatic motor neuron and all of the skeletal muscle fibers that is activates.
    motor unit
  5. The delay, which last about 2 msce; The muscle action potential sweeps over the sarcolemma and calcium ions are released from the sarcoplasmic reticulum.
    latent phase
  6. Second phase, last 10-100 msec; during this time, Ca2t binds to troponin, myosin binding sites on actin are exposed, and cross bridges form.
    contraction period
  7. Peak tension develops in the muscle fiber. During the third phase also 10-100 msec, Ca2t is actively transported back into the sarcoplasmic reticulum, myosin binding sites are covered by tropomyosin, myosin heads detach from actin, and tension in the muscle fiber decreases.
    relaxation period
  8. When a skeletal muscle fiber is stimulated at rate of 20 to 30 times per second, it can only partially relax between stimuli. The result is a sustained but wavering contraction called
    Unfused tetanus
  9. In which stimuli arriving at different times causes larger contractions
    Wave summation
  10. When a skeletal muscle fiber is stimulated at a higher rate of 80 to 100 times per second, it does not relax at all. The result is, a sustained contraction in which individual twitches cannot be detected.
    Fused Tetanus
  11. the process in which the number of active motor units increase
    Multiple motor unit recruitmen
  12. A sustained, partial contraction of portions of a skeletal or smooth muscle in response to activation of stretch receptors or a baseline level of action potentials in the innervating motor neurons
    Muscle tone
  13. The tension (force of contraction) developed in the muscle remains almost constant while the muscle changes its length
    Isotonic contraction
  14. Inability of a muscle to maintain its strength of contraction or tension; may be related to insufficient oxygen, depletion of glycogen, and/or lactic acid buildup
    Muscle fatigue
  15. The tension generated is not enough to exceed the resistance of the object to be moved, and the muscle does not change its length.
    Isometric contraction
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A&P Lab Test 3 (1)
2015-10-28 04:29:59
UofM Lab
UofM A&P Lab
test 3
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