Cellular level of muscles Continued

  1. The Sarcoplasmic Reticulum is a:
    series of tubes formed by membranes around each myofibril. Is similar to smooth endoplasmic reticulum.
  2. The action of the Sarcoplasmic Reticulum is to:
    Store the calcium ions in relaxed muscle.
  3. What are the dilated ends of a section of the sarcoplasmic reticulum called:
    Terminal cisterns
  4. Describe what a Transverse Tubule looks like:
    Tunnel like infoldings of the sarcolemma that extend inward at right angles to the myofilaments
  5. Each sarcomere has ______ and are filled with _____________ _______
    two T Tubules, extracellular fluid.
  6. Triad=
    transverse tubule + 2 terminal cisterns on either side of it.
  7. _______ are the basic functional units of striated muscle fibers.
  8. Sarcomeres are divided into _____ and _____
    bands and zones
  9. The Z-discs mark the divisions between _________
  10. Darker areas in the sarcomere is called the
    A Band
  11. The lighter area in the sarcomere is called the
    I Band
  12. The Transverse tubules are located at the junction between ____ and ____ bands
    A and I
  13. The ____ band has only thin filaments in relaxed muscle
    I band
  14. The __ zone within the A band have overlapping filaments.
    H zone
  15. Other parts of the __ band have overlapping filaments
  16. __ line is formed by proteins that connect adjacent thick filaments
    M line
  17. Z discs are places where:
    thick filaments are anchored
  18. During Contraction, thin filaments slide:
    inward toward the H zone
  19. Explain why Muscles shorten?
    filaments overlap but do not change in length
  20. Myosin molecules have a head and tail region what is the head also referred to as?
    Cross bridges
  21. In a relaxed muscle the heads become activated by energy from _____
  22. Actin molecules have myosin binding sites that are covered in a relaxed muscle by a regulatory molecule called?
  23. Another regulatory molecule called _____ is present in the thin filaments
  24. Signals from nerves result in:
    changes in the membrane of muscle that travels into the transverse tubule system to release of calcium ions from the sarcoplasmic reticulum
  25. The _____ ____ combine with tropin , causing it to change shape
    calcium ions
  26. The shape change moves the _______ and the _______ away from the myosin binding sites.
    troponin and the tropomyosin
  27. The activated myosin heads bind to the myosin-binding sites on _____
  28. When the nerve stops stimulating the muscle, muscle action potentials _____
  29. During _______, calcium stops being released from the sarcoplasmic reticulum and is pumped back into
  30. Explain Rigor Mortis (rigidity of death)
    Calcium leaks out and the cross bridges attach, No ATP produced so cross bridges cant detach
  31. When does Rigor Mortis begin
    3-4 hours after death, peaks at about 12 hours
  32. When does Rigor Mortis end:
    Diminishes over the next 48-60 hours as tissues begin to disintegrate.
  33. Maximum force is exerted when maximum number of ______ ______ make contact
    cross bridges
  34. At ______ ______, fewer cross bridges can bind
    longer lenghts
  35. At ______ _______, thick filaments crumple
    short lenghts
  36. Maximum force is exerted at ________ ________
    intermediate lenghts
  37. Neurons that stimulate muscles to contract are _____ ______
    motor neurons
  38. A motor neuron and all the skeletal muscle fibers it stimulates=
    a motor unit
  39. All the fibers of a ____ _____ contract and relax together
    motor unit
  40. ________ is the minimum voltage necessary to produce contraction.
  41. Amount of force generated on muscles depends on 4 factors which are:
    length of muscle fibers before they contract, Number of muscle fibers contracting, The structure of muscle (arrangement of fascicles) and the Frequency of stimulation
  42. The number of muscle fibers contracting depends n the number of _____ ______ and the ____ of an individual____ _____
    motor unit, size, motor unit
  43. The process of increasing the number of active motor units
  44. Twitch Contraction is a:
    briefd contraction of all the fibers in a motor unit in response to a single action potential in the motor neuron
  45. First Part of Twitch contraction = latent period where:
    calcium is released and slack taken up in the system
  46. Second Part of Twitch contraction= contraction phase:
    muscle tension increases
  47. Third Part of Twitch contraction= ________ phase in which calcium ions are taken back up and muscle tension decreases.
  48. Wave (temporal summation) is caused by?
    a stimuli that arrives after the refractory period but before the relaxation period is over
  49. In the ________ period a muscle that has contracted temporarily loses its ability to contract.
  50. What is Tetanus
    no relation between stimuli
  51. What the cause of Muscle Fibers?
    few muscle fibers are contracted involuntarily at a given time.
  52. What is the cause of Cramps?
    Painful, spasmodic contractions triggered by the spinal cord
  53. Cramps are initiating by:
    irritating factors such as extreme cold, heavy exercise, lack of blood flow, electrolyte depletion, dehydration, or low blood glucose.
  54. All fibers of a single motor are of the:
    same type
  55. Nearly all muscles have a mixture of _____ twitch and _____ twitch motor units in them but the proportions differ according to each muscles function.
    slow and fast
  56. Slow-twitch fibers are:
    • smaller have abundant mitochondria, capillaries, myoglobin , Are RED, low glycogen content, aerobic respiration, resistant to fatigue,¬†
    • Examples: Soleus and postural muscles of spinal column
  57. Fast- Twitch fibers are:
    • Larger, fewer mitochondria, capillaries and low myoglobin content, and WHITE, high glycogen content, anaerobic,poor resistant to fatigue¬†
    • Examples: Gastrocnemius, biceps brachii
  58. Slow twitch muscles are used in:
    Endurance activities
  59. Fast-Twitch are used int:
    Rapid intense movements of short duration
Card Set
Cellular level of muscles Continued