Unit 4 definitions.txt

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Unit 4 definitions.txt
2012-04-09 01:03:28
Exercise physiology unit definitions

Exercise physiology unit 4 definitions
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  1. action potential?
    A momentary change in electrical potential on the surface of a cell, especially of a nerve or muscle cell, that occurs when it is stimulated, resulting in the transmission of an electrical impulse.
  2. all-or-none principle?
    Principle that states if a stiumulus triggers an action potential in the motor neuron, all of the muscle fibers will contract synchronously.
  3. afferent neuron?
    Nerve signals thraveling toward the CNS and enters the spinal cord via the dorsal root.
  4. autonomic nervous system?
    Controls involuntary muscle contractions such as in smooth muscles of the intestines and myocardium. Contains the sympathetic and para-sympathetic responses.
  5. central nervous system?
    Comprised of the brain and spinal cord.
  6. efferent neuron?
    Nerve sinals leaving and traveling away from the CNS exiting via the ventral root to supply extrafusal and intrafusal skeletal muscle fibers.
  7. Golgi tendon organs?
    Sensory proprioceptors located in tendons and connected to the muscle's extrafusla fibers. They detect differences in muscle tension. Excessive muscle tension casues reflex inhibition of the muscles.
  8. myofibril?
    Contractile filaments that make up striated muscle fiber.
  9. myofilament?
    A smaller sub-unit of a myofibril that runs parallel with myofibrils. They consists mainly of the proteins actin and myosin.
  10. proprioceptors?
    Sensory receptor sensitive to stretch, tension, and pressure. They relay information about muscular dynamics such as limb position and kinesthesia. These help us keep our balance.
  11. sarcoplasmic reticulum?
    Enhances the cells structural integrity and includes an extensive interconnecting network of tubular channels and vesicles. It allows a wave of rapid depolarization through the T-tubular system during muscular contraction. Contains Ca pumps.
  12. temporal summation?
    A neuron generates an action potential when many subthreshold excitatory impulses arrive in rapid succession.
  13. concentric contraction?
    The shortening of a muscle while during contration.
  14. delayed onset muscle soreness?
    • Residual sorness from an unaccustomed exercise that may last for 3-4 days. Caused by:
    • -minute muscle tears
    • -osmotic pressure changes causing fluid retention
    • -muscle spasm
    • -acute inflammation
    • -alteration in cell's mechanism for calcium regulation
  15. eccentric contraction?
    The lengthening of a muscle while during contraction.
  16. fiber hyperplasia?
    Increase in muscle fiber numbers.
  17. fiber hypertrophy?
    Increase in muscle fiber size.
  18. isokinetic contraction?
    Muscle action performed at constant angular limb velocity. Same speed.
  19. isometric contraction?
    Muscle action without noticeable change in muscle length.
  20. isotonic contraction?
    Tension remains unchanged and the muscle's length changes during muscle contraction.
  21. periodization?
    Variation in training volume and intensity over a specified time period; the goal is to prevent staleness while peaking physiologically for competition.
  22. plyometrics?
    Resistance training involving eccentric-to-concentric actions performed quickly so a muclse stretches slightly before the concentric action, using the stretch reflex to augment the muscle's force-generating capacity.