Muscle System (a)

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Muscle System (a)
2013-07-16 23:57:56
muscle system

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  1. Essay: Steps of muscle contraction
    • 1. Acetylcholine released from the axon terminal binds to receptors on the sarcolemma.
    • 2. An action potential is generated and travels down the T tubule
    • 3. Ca2+ is released from the sarcoplasmic reticulum in response to the change in voltage
    • 4. Ca2+ binds troponin; Cross-bridges from between actin and myosin
    • 5. Acetylcholinesterase removes acetylcholine from the synaptic cleft.
    • 6. Ca2+ is transported back into the sacroplasmic reticulum
    • 7. Tropomyosin binds active sites on actin causing the cross-bridge to detach
  2. The capacity of a muscle cell to shorten forcefully is known as
  3. Muscles exhibit the property of excitability. 
    This means that the muscle
    responds to stimulation by the nervous system
  4. Identify the general functional characteristics of muscle
    Muscle tissue shortens forcefully but lengthens passively
  5. Acetylcholine binds to a membrane bound receptor and causes ligand-gated sodium channels to open and results in
  6. Which of the following actions caused by contraction of skeletal muscle
    moving your feet in walking
  7. Smooth muscle and cardiac muscle are similar in that they are both
  8. Smooth Muscle-
    • A calcium-calmodulin complex initiates cross bridge formation
    • Multiunit smooth muscle is located wall of blood vessels
    • depolarizes when both sodium and calcium ions diffuse into the cell.
  9. Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the
    size of muscle fibers
  10. Skeletal muscle fibers develop from
  11. Fasciculi
    is surrounded by perimysium
  12. Fascia
    surrounds individual muscles
  13. Endomysium
    surrounds each muscle fiber
  14. Lack of acetylcholinesterase in the synaptic cleft would result in
    continuous stimulation of the postsynaptic membrane
  15. List the following structures in order from smallest to largest
    myofilament --> myofibril-->muscle fiber--> muscle fasciculus
  16. Which of the following will respond to a threshold stimulus with an all-or-none contraction?
    A & B a single muscle fiber & a single motor unit (d)
  17. Which of the following is called the thin myofilament?
  18. Troponin
    has a calcium-binding site
  19. Which of the following is composed of myosin molecules
    thick myofilaments
  20. The active sites to which cross-bridges attach are found on the
    actin myofilaments
  21. You are hired to work in a laboratory to measure the rate of human muscle contraction. Which of the following might decrease in quantity in muscle cells undergoing contractions?
  22. T tubules are invaginations of the
  23. T tubules
    conduct action potentials deep into the muscle cell
  24. Sarcoplasmic reticulum
    stores calcium ions
  25. Sliding filament model
    Both actin and myosin myofilaments shorten during contraction (false statement)
  26. If sodium ions cannot enter a muscle fiber in response to a stimulus,
    contraction cannot occur
  27. (Neuromuscular junctions) The
    sites where a chemical substance is transmitted from the presynaptic terminal
    of an axon to the postsynaptic membrane of a muscle fiber are called
    Neuromuscular junctions
  28. A drug that interferes with the active transport of calcium ions from the sarcoplasm back into sarcoplamic reticulum would result in
    contraction with no relaxation
  29. ATP molecule is required
    • (*e*) A, B, C
    • A)for formation of the cross-bridge.
    • B) for movement of the cross-bridge.
    • C) for release of the cross-bridge.
  30. After contraction has occurred,
    released from troponin
  31. Depolarization of the cell membrane occurs when there is a rapid influx  (inflow) of
    Sodium ions
  32. an all or non-response
  33. synaptic vesicles in the neuromuscular junction contain
  34. Curare blocks acetylcholine receptors at the motor end plate.  This would result in
    inability of the muscle fiber to respond to nervous stimulation
  35. Arrange these structures as they participate in excitation
    sarcolemma, T tubules, sarcoplasmic reticulum, calcium ions
  36. Arrange the following list of biochemical events in the correct sequence
    • 1. An action potential is conducted deep into the muscle fiber by the T tubule
    • 3. The membranes of the sarcoplasmic reticulum become more permeable to calcium ions.
    • 4. Calcium ions diffuse into the sarcoplasm around the myofibril.
    • 2. Calcium ions bind to troponin.
    • 5.  The troponin-tropomyosin complex moves exposing active sites

  37. Movement of the myosin molecule while the cross bridge is attached in a ________
    power stroke
  38. During the contraction phase of a muscle twitch
    actin-myosin cross-bridges form.
  39. Tetanus of a muscle is thought to be caused by
    high calcium ion concentrations in the sarcoplasm
  40. Rigor mortis occurs after death because
    cross-bridges form but can't release.
  41. Oxygen debt
    amount of oxygen that cells need to replenish ATP supplies after exercise.
  42. Consider the following four phrases and select the one that does not belong with the others
    fuels runner in a marathon
  43. Which of the following correctly describes myoglobin's special function in muscle tissue?
    acts as a reservoir for oxygen
  44. Muscle atrophy
    is characterized by a decrease in muscle size