46. Ca2+ must bind to tropomyosin so that the myosin binding sites on actin will be accessible tothe myosin. 47. The _________ complex contains three proteins designated as the I, T, and C types. 48. The movement of the troponin-tropomyosin complex requires 49. The actin filament is a polymer formed from 300 to 400 globular subunits called 50. Transverse tubules contain voltage-gated calcium channels that respond to membrane depolarization and are directly coupled to the calcium release channels in the sarcoplasmic reticulum. 51. The Ca2+ required for skeletal muscle contraction
52. The pumps that actively transport calcium back into the _______ are called Ca2+ -ATPase pumps. 53. When a muscle is stimulated to contract, calcium release channels in the SR will release Ca2+ by 54. What structures carry the action potentials into the interior of the muscle to cause muscle contraction? A.T tubules B. terminal cisternae C. sarcoplasmic reticula D. ryanodine receptors 55. The process by which action potentials cause muscle contraction is 56. Which of the following is NOT true of the relaxation of a muscle fiber? 57. What is the role of ATP in muscle contraction and relaxation? 58. Summation occurs in muscle cells when stimulus frequency increases to produce a greater force contraction. 59. Increasing the frequency of action potentials in a somatic motor neuron will induce increasedforce of muscle contraction.
60. The inability of muscle cells to relax due to high frequency stimulation is termed
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- Fall '11