1. An example of a partial but sustained contraction is A. eye blinking. B. muscle tone. C. knee jerking. D. a twitch.

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1 BIOL 2010 Human A&P I -- Exam 4 -- FORM A -- Name: 1. An example of a partial but sustained contraction is A. eye blinking. B. muscle tone. C. knee jerking. D. a twitch. 2. In order for muscle relaxation to occur, A. sodium ions must be actively transported to troponin. B. the active sites on myosin must be uncovered. C. the active sites on actin must be blocked. D. power strokes slow down. E. calcium ions must be transported to troponin. 3. The capacity of a muscle cell to shorten forcefully is known as A. extensibility. B. excitability. C. flexibility. D. elasticity. E. contractility. 4. Oxygen debt in muscles may develop because of A. too high a concentration of oxygen in the atmosphere. B. the inability of myoglobin molecules to store enough oxygen when skeletal muscles are used strenuously for a minute or two. C. too much oxygen used in forming pyruvic acid when skeletal muscles are contracted strenuously for a minute or two. D. the inability of respiratory and circulatory systems to supply enough oxygen to skeletal muscles when used strenuously for a minute or two. 5. The rotator cuff muscles A. attach at the distal end of the humerus. B. fix the scapula in place. C. attach the clavicle to the humerus. D. attach the arm to the thorax. E. hold the head of the humerus in the glenoid fossa of the scapula. 6. Myosin is also known as the A. thick myofilament. B. sarcomere. C. thin myofilament. D. intermediate myofilament. E. short myofilament.

2 7. The deepest muscle of the abdominal wall is the A. transverse abdominal. B. pectoralis minor. C. internal oblique. D. latissimus dorsi. E. rectus abdominis. 8. Threshold stimulus is the A. maximum stimulus required to release acetylcholine. B. minimum stimulus required to produce ATP. C. maximum stimulus required to contract a muscle. D. minimum strength of stimulation required to contract a muscle fiber. 9. Which of the following is not true? A. Red fibers contain more myoglobin than white. B. Red fibers have fewer mitochondria than white. C. Red fibers contract more slowly than white. D. Red fibers fatigue more slowly than white. 10. Which of the following statements concerning types of muscle contractions is false? A. In isotonic contractions, the muscle fibers shorten. B. Most skeletal muscle contractions are a combination of isometric and isotonic contractions. C. In isometric contractions, the amount of tension produced by the muscle is constant. D. In isotonic contractions, the amount of tension produced by the muscle fibers is constant during the contraction. E. The contractile processes in isometric and isotonic contractions are the same. 11. Which of the following is a part of the quadriceps femoris muscle group? A. tensor fasciae latae B. sartorius C. vastus lateralis D. pectineus E. iliotibial tract 12. If a man exercises by doing push-ups every day, he would strengthen or enlarge which of the following muscles? A. biceps brachii B. triceps brachii C. supraspinatus D. gastrocnemius E. thenar muscles 13. Bones and muscles function as mechanical devices called A. lifts. B. ladders. C. syncytia. D. levers.

3 14. 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 A. sarcomeres. B. cell body of neuron. C. myofilaments. D. Z disks. E. neuromuscular junctions. 15. A condition in which stimuli occur so rapidly that there are no intervening relaxations between contractions is called A. complete tetanus. B. treppe. C. all or none tetanus. D. involuntary paralysis. E. incomplete tetanus. 16. Which of the following statements concerning slow-twitch oxidative muscle fibers is false? A. They are well adapted to anaerobic activity. B. They have large deposits of myoglobin. C. They have a well developed blood supply. D. They have low glycogen stores. E. They split ATP slowly. 17. List the following structures in order from smallest to largest. (1) muscle fiber (2) myofilament (3) myofibril (4) muscle fasciculus A. 4, 2, 3, 1 B. 2, 3, 1, 4 C. 1, 2, 3, 4 D. 3, 1, 4, 2 E. 2, 1, 4, A sarcomere is the A. structural and functional unit of the skeletal muscle cell. B. cell membrane of a muscle fiber. C. cytoplasm of muscle cells. D. protein strand composed of actin or myosin. E. contractile thread that extends the length of the muscle fiber. 19. Which type of respiration occurs in the mitochondria? A. anaerobic respiration B. aerobic respiration C. both anaerobic and aerobic respiration

4 20. During short periods of intense exercise, energy in muscles is primarily derived from A. anaerobic respiration. B. creatine phosphate breakdown. C. both anaerobic respiration and creatine phosphate breakdown. D. nuclear reactions. E. aerobic respiration. 21. Rigor mortis affects skeletal muscles a few hours after death, due to A. an increase in ATP and decreased permeability to calcium. B. a decrease in ATP and increased permeability to calcium. C. an increase in ATP. D. impulses that produce sustained contractions. 22. Identify the statement concerning general functional characteristics of muscle that is true. A. Muscle tissue shortens forcefully but lengthens passively. B. Muscle tissue can get shorter, but cannot get longer. C. Muscle tissue can get longer, but cannot get shorter. D. Muscle tissue shortens passively but lengthens forcefully. E. None of these statements are true. 23. Intense exercise that results in a great deal of anaerobic activity A. decreases the efficiency of fast-twitch fibers. B. converts some slow-twitch fibers into fast-twitch fibers. C. enlarges slow-twitch fibers. D. increases muscular strength and mass. E. decreases muscle strength and mass. 24. One ATP molecule is required for A. movement of the cross-bridge. B. formation of the cross-bridge. C. formation of the cross-bridge and for movement of the cross-bridge. D. release of the cross-bridge. E. formation of the cross-bridge, for movement of the cross-bridge, and for release of the cross-bridge. 25. Channels that open or close in response to changes in the electrical charge or voltage across the plasma membrane are called A. leak ion channels. B. relegated ion channels. C. ligand-gated ion channels. D. obligated ion channels. E. voltage-gated ion channels. 26. When the myosin head flexes into a bend, pulling the actin filament along with it, this is called the A. power stroke. B. action reaction. C. muscle tone. D. action potential. E. recovery stroke.

5 27. After taking their wedding vows, a bride and groom often ceremonially use which of the following muscles before walking away from the altar? A. quadriceps femoris B. orbicularis oris C. platysma D. levator labii superioris E. depressor anguli oris 28. Which type of muscle tissue is multinucleated? A. smooth muscle B. both cardiac and smooth muscle C. skeletal muscle D. cardiac muscle E. both skeletal and cardiac muscle 29. Aerobic exercise A. can increase the number of mitochondria in muscle cells. B. increases vascularity of muscle. C. develops fatigue-resistant fast-twitch fibers. D. can increase the efficiency of slow-twitch fibers. E. All of these choices are correct. 30. Synaptic vesicles in the neuromuscular junction contain A. acetylcholine. B. ATP. C. sodium. D. acetylcholinesterase. E. calcium. 31. When comparing smooth and skeletal muscle cells, which of the following statements is true? A. Smooth muscle has a lot of actin and myosin. B. Smooth muscle cells are larger than skeletal muscle cells. C. Smooth muscle cells have striations. D. Smooth muscle cells are multinucleated. E. The myofilaments in smooth muscle do not form sarcomeres. 32. A waste product of anaerobic respiration in muscle cells is A. carbonic acid. B. pyruvic acid. C. lactic acid. D. uric acid. E. hydrochloric acid. 33. Muscle atrophy A. is characterized by an increase in muscle size. B. causes an increase in blood flow to the affected muscle. C. results from aerobic exercise. D. is characterized by a decrease in muscle size. E. involves an increase in the number of muscle fibers.

6 34. The flexion of the elbow represents a A. class I lever system. B. nonlever system. C. class IV lever system. D. class II lever system. E. class III lever system. 35. One ATP molecule is required for A. formation of the cross-bridge, for movement of the cross-bridge, and for release of the cross-bridge. B. formation of the cross-bridge and for movement of the cross-bridge. C. release of the cross-bridge. D. formation of the cross-bridge. E. movement of the cross-bridge. 36. The type of muscle fatigue known as "psychological fatigue" is the result of A. the emotional state of an individual. B. increased calcium ion concentration in the sarcoplasm. C. depleted ATP reserves. D. decreased levels of acetylcholine. E. None of these choices is correct. 37. Which of the following muscles of mastication would be responsible for mandibular elevation? A. stylohyoid B. lateral pterygoid C. temporalis D. zygomaticus minor E. zygomaticus major 38. The outside of the resting plasma membrane is relative to the inside of the resting plasma membrane. A. positively charged B. negatively charged C. None of these choices is correct. D. recharged E. electrically neutral 39. A drug that interferes with the active transport of calcium ions from the sarcoplasm back into the sarcoplasmic reticulum would result in A. fibrosis of the muscle. B. muscle hypertrophy. C. relaxation of the muscle fiber. D. an imbalance of blood calcium. E. contraction with no relaxation. 40. A fasciculus A. possesses an external lamina. B. is surrounded by perimysium. C. is a bundle of reticular fibers. D. is a bundle of collagen fibers. E. is only found in smooth muscle.

7 41. Which of the following statements concerning types of muscle contractions is false? A. Most skeletal muscle contractions are a combination of isometric and isotonic contractions. B. The contractile processes in isometric and isotonic contractions are the same. C. In isotonic contractions, the muscle fibers shorten. D. In isotonic contractions, the amount of tension produced by the muscle fibers is constant during the contraction. E. In isometric contractions, the amount of tension produced by the muscle is constant. 42. The active sites to which cross-bridges attach are found on the A. actin myofilaments. B. T tubules. C. sarcoplasmic reticulum. D. Z disks. E. myosin myofilaments. 43. Smooth muscle and cardiac muscle are similar in that they both A. are widely distributed in the body. B. are striated. C. have multiple nuclei. D. are under voluntary control. E. are under involuntary control. 44. A child ingested an organophosphate poison used to kill insects. Soon the child's muscles began spastic contractions. Predict what occurred at the synaptic cleft. A. the poison binds to acetylcholine receptors and stimulates them B. increased accumulation of acetylcholine in the synapse C. Both increased accumulation of acetylcholine in the synapse and increased breakdown of acetylcholine in the synaptic cleft. D. increased breakdown of acetylcholine in the synaptic cleft E. decreased release of acetylcholine from presynaptic neurons 45. During short periods of intense exercise, energy in muscles is primarily derived from A. both anaerobic respiration and creatine phosphate breakdown. B. anaerobic respiration. C. aerobic respiration. D. creatine phosphate breakdown. E. nuclear reactions. 46. The biceps femoris is part of the A. medial thigh compartment. B. quadriceps group. C. thigh and hip adductors. D. anterior thigh compartment. E. hamstrings. 47. Which of the following muscles would be considered an antagonist to the rectus femoris? A. biceps femoris B. vastus lateralis C. gracilis D. sartorius E. vastus intermedius

8 48. Which of the following events occurs during the lag phase of a muscle twitch? A. The action potential is propagated from presynaptic to postsynaptic membrane. B. Calcium is pumped back into the sarcoplasmic reticulum. C. Cross-bridges form, move, release, and reform many times. D. Muscle fibers shorten. E. All of these events occur in the lag phase. 49. Muscles exhibit the property of excitability. This means that the muscle A. recoils to its original resting length. B. shortens its length. C. excites itself. D. responds to stimulation by the nervous system. E. stretches beyond its normal length. 50. When you "pull your tummy in" and compress your abdomen, you use the rectus abdominis, external abdominal oblique, internal abdominal oblique, and transversus abdominis muscles. This is an example of muscles working as A. fixators. B. cooperatives. C. antagonists. D. prime movers. E. synergists. 51. An isometric contraction is described as A. action potential frequency is high enough that no relaxation of muscle fibers occurs. B. a muscle produces tension, but the length of the muscle is increasing. C. a muscle produces an increasing tension as the length remains constant. D. a muscle produces constant tension during contraction. E. a muscle produces increasing tension as it shortens. 52. At a neuromuscular junction A. neurotransmitters are released. B. troponin and tropomyosin exchange places. C. actin and myosin filaments slide past one another. D. intercalated discs are synthesized. 53. Curare blocks acetylcholine receptors at the motor end plate. This would result in A. lack of calcium uptake by the muscle fiber. B. more acetylcholinesterase production. C. inability of the muscle fiber to respond to nervous stimulation. D. increased stimulation of the muscle. E. sustained contraction of the muscle. 54. Binding sites on the surface of actin allow the formation of cross-bridges with molecules of A. troponin. B. tropomyosin. C. myosin. D. ATP.

9 55. Which type of muscle tissue has spindle-shaped cells? A. smooth muscle B. both skeletal and cardiac muscle C. skeletal muscle D. both cardiac and smooth muscle E. cardiac muscle 56. Concentric contractions occur when A. tension in a muscle is maintained while the muscle increases in length. B. the muscle produces increasing tension as it shortens. C. the tension and length of the muscle remain constant during a contraction. D. isometric contractions occur. E. the muscle produces tension while the length of the muscle increases. 57. Which of the following is true? A. Smooth muscle is found in the walls of hollow organs. B. There is a small amount of smooth muscle in the heart. C. Cardiac muscle cells have multiple nuclei. D. Smooth muscle cells are long and cylindrical. E. Skeletal muscle is capable of spontaneous contraction. 58. Myosin phosphatase A. removes phosphate from myosin. B. activates myosin kinase. C. binds to calcium-calmodulin complex. D. forms the cross-bridge. E. opens calcium channels. 59. The sternocleidomastoid muscle extends from the mastoid process of the temporal bone to the sternum and medial clavicle. When both sternocleidomastoid muscles contract, the head is flexed. The end of the muscle that connects to the sternum is the A. insertion. B. belly. C. origin. D. fixator. E. body. 60. Which of the following muscles is named for its shape? A. pectoralis major B. trapezius C. pectoralis minor D. vastus lateralis E. adductor pollicis 61. The enzyme acetylecholinesterase causes acetylcholine to A. bind to actin. B. be secreted from the motor end plate. C. decompose. D. form cross-bridges.

10 62. Whole muscles can respond in a graded fashion to stimuli by varying A. the number of motor units recruited. B. the force of contraction of individual muscle fibers. C. the amplitude of the action potential. D. thresholds. E. the frequency of stimulus. 63. Muscle myofibrils A. extend from the sarcolemma to the T-tubule. B. are found in the sarcolemma. C. contain myosin and actin myofilaments. D. hold muscle cells together. E. do not appear striated. 64. Which of the following statements is correct? A. Actin filaments slide along myosin filaments. B. Filaments of troponin and tropomyosin slide past one another. C. Cross-bridges form between actin and the sarcolemma. D. Tropomyosin molecules move and expose specific sites on myosin filaments. 65. Which of the following statements regarding the sliding filament model is false? A. Both actin and myosin myofilaments shorten during contraction. B. The I band and H zones become narrower during contraction. C. Actin and myosin do not shorten during contraction. D. The A band remains constant in length. E. The sarcomere shortens. 66. Which of the following is true? A. The greatest amount of tension is achieved when actin and myosin do not overlap. B. Overstretching a muscle will increase its tension. C. The greater the overlap of actin and myosin, the stronger the contraction. D. Optimal actin and myosin overlap will produce maximal contraction. E. Tension is great when actin and myosin overlap as much as they can. 67. Creatine phosphate A. supplies energy for the breakdown of ATP to ADP. B. causes the decomposition of ATP. C. supplies energy for the synthesis of ATP. D. causes the decomposition of ADP. 68. The sarcoplasmic reticulum A. covers the muscle fiber. B. shortens during muscle contraction. C. transmits nerve impulses to the myofibrils. D. connects adjacent sarcomeres. E. stores calcium ions.

11 69. The region of the sarcomere that contains both actin and myosin myofilaments is called the A. H zone. B. Z disk. C. A band. D. I band. E. M line. 70. Depolarization of the cell membrane occurs when there is a rapid influx (inflow) of A. sodium ions. B. chloride ions. C. calcium ions. D. potassium ions. E. amino acids. 71. Transverse tubules A. connect actin and myosin. B. store sodium ions for the action potential at the cell surface. C. store calcium ions. D. transmit muscle impulses into the cell interior. 72. Which type of respiration produces ATP molecules? A. both anaerobic and aerobic respiration B. anaerobic respiration C. aerobic respiration 73. Oxygen deficit represents A. the amount anaerobic metabolism must increase after exercise. B. the amount of oxygen converted to lactic acid during exercise. C. the amount of oxygen that cells need to replenish ATP supplies after exercise. D. conversion of pyruvic acid to lactic acid. E. the amount of carbon dioxide that cells need to eliminate. 74. Troponin A. binds to ATP. B. is part of the myosin myofilament. C. has two subunits. D. has a calcium-binding site. E. is a long, flexible protein. 75. Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the A. number of striations. B. number of nuclei within the muscle fibers. C. size of muscle fibers. D. number of muscle fibers. E. number of muscle cells.

12 76. Which of the following correctly describes myoglobin's special function in muscle tissue? A. acts as a reservoir for oxygen B. synthesizes ATP C. stores glucose D. produces action potentials E. breaks down glycogen 77. Which of the following statements is correct? A. Actin filaments slide along myosin filaments. B. Tropomyosin molecules move and expose specific sites on myosin filaments. C. Filaments of troponin and tropomyosin slide past one another. D. Cross-bridges form between actin and the sarcolemma. 78. Arrange the following steps of muscle fiber contraction in the correct sequence. 1. The muscle impulse reaches the sarcoplasmic reticulum and calcium is released. 2. Thin filaments are pulled over the thick filaments. 3. Calcium floods the sarcoplasm and binds to troponin molecules leaving active sites. 4. The impulse arrives at the synapse and travels through the transverse tubules. 5. The muscle fiber shortens and contracts. 6. Myosin heads bind to exposed active sites on actin, forming cross-bridges. A. 4, 1, 3, 2, 6, 5 B. 4, 1, 3, 6, 2, 5 C. 4, 3, 6, 2, 5, 1 D. 4, 1, 3, 5, 6, Endomysium is a delicate network of loose connective tissue that A. surrounds each muscle fiber. B. is composed of elastic fibers. C. separates individual muscles. D. forms a sheath around a fasciculus. E. penetrates muscle fibers. 80. 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. (2) Calcium ions bind to troponin. (3) The membranes of the sarcoplasmic reticulum become more permeable to calcium ions. (4) Calcium ions diffuse into the sarcoplasm around the myofibril. (5) The troponin-tropomyosin complex moves exposing active sites. A. 1, 4, 3, 2, 5 B. 1, 5, 2, 3, 4 C. 1, 2, 3, 4, 5 D. 1, 3, 4, 2, 5 E. 1, 3, 2, 5, 4