AP151 MUSCLE STUDY GUIDE
READ
TEXT BOOK: Chapter 12
 Pgs. 356-371, stop at “Treppe”
 Pgs. 373-378, stop at “adaptations to exercise training”
 Figures 12.10, 12.11, 12.12, 12.14, 12.16, 12.16, 12.17, 12.22, 12.24 & 12.26 are good
summaries
 Tables 12.2, 12.3 are good summaries
VISUAL ANALOGY GUIDE
 pg 50-55
MAJOR OBJECTIVES/OUTCOMES—STUDENTS SHOULD BE ABLE TO:
1. Describe the basic functional anatomy of skeletal muscle (mostly self review)
2. Explain the structure and function (sequence of events) at a NMJ and how those events
lead to stimulation of a muscle fiber
3. Explain excitation-contraction coupling including the cause-effect relationship of events in
excitation-contraction coupling.
4. Explain the sliding filament theory of contraction (how muscles contract) including the
cause effect relationships among events of leading to contraction and relaxation.
5. Explain the events that occur in a twitch and what factors influence tension (i.e., strength
of contraction) including cause-effect relationships
6. Explain the metabolic activity of muscle (muscle energetic) and how substrates and
production of ATP changes based on duration and intensity of muscle activity
7. Describe the factors that contribute to muscle fatigue
8. Describe the different muscle types
9. Describe the changes that typically occur in muscle/body as a result of physical training.
STUDY QUESTIONS
Muscle Structure Review Questions:
1. What is a motor unit
2. How is the size of motor units related the precision of movement the muscle can
perform?
3. What is a motor end plate?
4. What is a t-tubule
5. What is the sarcoplasmic reticulum and what does it do?
6. How does the SR acquire calcium?
7. What are the names of the proteins that the SR uses to release Ca+
8. Describe the organization of actin (thin) and myosin (thick) filaments including what a zline and sarcomere are.
9. What are the three parts of a actin/thin filament
Explain the structure and function (sequence of events) at a NMJ and how those events
lead to stimulation of a muscle fiber
1. What is a nueromuscluar junction
2. What two types of cells create a neuromuscular junction?
3. What part of the motor neuron is found at a NMJ?
4. What part of the muscle fiber is adjacent to the synaptic cleft?
5. What neurotransmitter is released at a neuromuscular junction?
6.
7.
8.
9.
What kind of channels are on the synaptic knob?
What events or conditions lead to the release of the NT into the synaptic cleft?
What kind of receptors does the NT bind to on the motor end plate?
What happens when the NT binds the receptors on the motor end plate (i.e., What ion in
allowed into the muscle fiber once the receptors are activated)?
10. Explain how the post-synaptic membrane/motor end plate depolarizes the muscle cell
and leads to an AP.
11. How many AP from the motor neuron does it typically take to bring the muscle cell to
threshold?
12. What stops/prevents continuous stimulation of the receptor by the NT in neuromuscular
junction?
13. How does botulism toxin (and Botox) prevent muscle contraction (i.e., cause paralysis)?
14. How do AChE (acetylcholinesterase) inhibitors/ blockers cause muscle dysfunction?
15. What part of the central nervous system initiates voluntary muscle activity?
16. What parts of the central nervous system can initiate reflexive muscle activity?
17. What parts of the brain are involved with the coordination of muscle activity?
18. How many neurons is each skeletal muscle innervated by?
19. Are all skeletal muscle cells innervated by a motor neuron?
Explain excitation-contraction coupling including the cause-effect relationship of events
in excitation-contraction coupling.
20. When skeletal muscle cells depolarize what ions move into the cell?
21. Through what kind of channels does the ion (from question above) move through during
an AP on a muscle cell?
22. When an AP passes into the t-tubules what kind of channels (also sometimes known as
receptors) will the AP cause to open (hint: I’m not referring to VG Na+ channels)?
23. What is the function of the voltage gated calcium channels (DHP receptors) in the Ttubules? What opens them?
24. Where are the calcium release channels (ryanodine receptors) located within a muscle
cell?
25. What structure/events directly causes the opening of the calcium release channels?
26. What is the relationship between the DHP receptors (VG Ca+ channels) and the release
of Ca+ from the SR?
27. When does the SR release Ca+?
28. What happens to the Ca+ concentration of the cytoplasm when the SR releases calcium?
29. What will rising Ca+ concentrations in the cytoplasm cause to happen?
30. If the muscle is not stimulated again what happens to the Ca+ within the cytoplasm?
31. Write a step by step account of the events involved with excitation-contraction coupling
beginning with depolarization of the cell membrane and ending with the binding of
calcium to troponin.
Explain the sliding filament theory of contraction (how muscles contract) including the
cause effect relationships among events of leading to contraction and relaxation.
32. What part of a thin/actin filament do myosin heads bind to?
33. What part of an actin filament does Ca+ bind to?
34. What part of an actin filament covers up the binding sites for the myosin head?
35. What is the role of troponin in muscle contraction and relaxation
36. What is the role of calcium in muscle contraction and relaxation—specifically the
interactions between myosin and actin
37. What molecule activates/energizes the myosin head?
38. What two molecules are needed for muscle to contraction to occur through filament
interaction
39. Explain two ways ATP is important for actin and myosin to interact and cause contraction.
40. At what stage in filament interactions does ATP bind the myosin head?
41. At what stage in filament interation is ATP broken down?
42. AT what stage in filament interaction does ATP (ADP + P) leave the head?
43. What happens to contraction when calcium is no longer available within the cytoplasm?
44. What causes Ca+ levels to decline and eventually cause muscle relaxation?
45. Do the actin and myosin filaments get smaller during contraction?
46. What happens to the amount of overlap between actin and myosin during muscle
contraction?
47. Write out a step by step explanation of how actin and myosin slide past one another to
produce contraction beginning with the release of calcium from the SR
Explain the events that occur in a twitch and what factors influence tension (i.e., strength
of contraction) including cause-effect relationships
48. What is a twitch?
49. What is the latent period and what is happening during this time?
50. During the contraction phase what is happening within the muscle cell? What is
happening to the amount of tension produced?
51. What is happening in the cell during the relaxation phase? What is happening to the
amount of tension produced?
52. The presence and/or absence of what single substance determines when contraction and
relaxation begins and ends?
53. What happens to the force of contraction if a muscle cell is stimulated before it is
completely relaxed?
54. Why is the second (subsequent) contraction(s) stronger then the first if the muscle cell is
stimulated before relaxation finishes?
55. What is the relationship between the amount of calcium in the cytoplasm and strength of
muscle contraction?
56. What is summation?
57. What is incomplete (unfused) tetanus? How is it accomplished?
58. What is complete (fused) tetanus? How is it accomplished?
59. What is recruitment?
60. What is the primary way that the strength of muscle contraction is regulated?
61. How does the body accomplish smooth (non-jittery) muscle contraction?
Explain the metabolic activity of muscle (muscle energetic) and how substrates and
production of ATP changes based on duration and intensity of muscle activity
62. What processes/events in skeletal muscle require ATP?
63. How much stored ATP is there within a muscle cell (how long would it sustain activity)?
64. How much activity can the stored CP within a muscle sustain?
65. How much activity can be sustained by the anaerobic breakdown of the cells own
carbohydrate?
66. How much activity can be sustained by the aerobic breakdown of the cell’s own stored
carbohydrates?
67. Which of the above (previous 4 questions) would be initially used if you suddenly got up
and started performing heavy work?
68. What is aerobic capacity/Vo2 Max?
69. How does skeletal muscle substrate usage change with the intensity of exercise under
under both short and long term muscle use? See figure 12.22
70. When is creatine phosphate created and when is it used?
71. How is creatine phosphate used to generate ATP?
72. What substrate(s) are of primary importance during rest? Moderate activity? Heavy
activity?
73. Explain what is happening metabolically in resting muscle cells?
74. When the cell can make more ATP then it needs/can store what is the surplus ATP used
for/to do?
75. Explain what is happening metabolically in moderately active muscle cells.
76. Explain what is happening metabolically in highly active muscle cells.
77. When does the cell rely largely on lipids? Mostly on carbs? The muscles own
substrates? Substrates from blood?
Describe the different type of muscle fibers
78. Which is the quickest to fatigue? Slowest to fatigue
79. Which contract the quickest? Slowest?
80. Which use primarily aerobic respiration? Which use primarily anaerobic?
81. Which are highly vascular?
82. Which are rich in capillaries? Which have few capillaries?
83. Which muscle type is typically found in postural muscles?
84. Describe the basic similarities and differences between slow oxidative, slow glycolytic,
and fast glycolytic muscle in terms of the amount of mitochondria, capillaries, aerobic
capacity, glycolyitic/anaerobic capacity and resistance to fatigue.
Describe factors that can contribute/cause muscle fatigue
85. List the factors that can contribute to muscle fatigue.
Describe the changes that typically occur in muscle/body as a result of physical training.
86. List the changes that occur in response to physical training and include a very brief
explanation with each.
Describe the anaerobic respiration/the lactic acid pathway and how it generates ATP.
87. What is the most fundamental way anaerobic respiration is different than aerobic respiration?
88. When compared to aerobic respiration how much ATP does anaerobic respiration produce?
89. What common process does both aerobic and anaerobic respiration share?
90. What are the two major steps in the anaerobic pathway?
91. Where in a cell does anaerobic respiration take place?
92. Why does pyruvate need to be converted to lactic acid in the anaerobic pathway?
93. Is the basic chemical equation for the anaerobic pathway?
94. What happens to the NADH in lactic acid fermentation?
95. In most tissues, can anaerobic respiration be sustained for long periods of time? Why/Why not?
96. What basic affect(s) does the accumulation of lactic acid have on cells?
QUESTIONS FROM TEXT
1, 8-12, 17, 21, 24,