The α-motor neurons are the largest neurons in the spinal cord, with myelinated axons that exit the spinal cord through the ventral roots and travel in peripheral nerves to innervate muscles. From: Fundamental Neuroscience (Fourth Edition), 2013 1 1) Muscle tissue, one of the four basic tissue groups, consists chiefly of cells that are highly specialized for
2 2) Which of the following is a recognized function of skeletal muscle?
E) All of the answers are correct. 3 3) At each end of the muscle, the collagen fibers of the epimysium, perimysium, and endomysium, come together to form a
4 4) The dense layer of connective tissue that surrounds an entire skeletal muscle is the
5 5) Nerves and blood vessels that service a muscle fiber are located in the connective tissues of its
6 6) A fascicle is a
A) group of muscle fibers that are encased in the perimysium. 7 7) The delicate connective tissue that surrounds the skeletal muscle fibers and ties adjacent muscle fibers together is the
8 8) The bundle of collagen fibers at the end of a skeletal muscle that attaches the muscle to bone is called a(n)
9 9) Put the following structures in order from superficial to deep.
10 10) Interactions between actin and myosin filaments of the sarcomere are responsible for
11 11) In a sarcomere, the central portion of thick filaments are linked laterally by proteins of the
12 12) The advantage of having many nuclei in a skeletal muscle fiber is the ability to
D) produce large amounts of muscle proteins 13 13) Skeletal muscle fibers are formed from embryonic cells called
14 14) The repeating unit of a skeletal muscle fiber is the
15 15) The plasma membrane of a skeletal muscle fiber is called the
16 16) Which of the following best describes the term sarcomere?
B) repeating unit of striated myofibrils 17 17) Muscle fibers differ from "typical cells" in that muscle fibers
18 18) Which of the following best describes the term sarcoplasmic reticulum?
C) storage and release site for calcium ions 19 19) Which of the following best describes the term Z line?
D) thin filaments are anchored here 20 20) The region of the sarcomere containing the thick filaments is the
21 21) The skeletal muscle complex known as the triad consists of
B) a transverse tubule and two terminal cisternae. 22 22) Cross-bridges are portions of
23 23) The area in the center of the A band that contains no thin filaments is the
24 24) Each skeletal muscle fiber contains ________ myofibrils.
25 25) At rest, the tropomyosin molecule is held in place by
26 26) Each thin filament consists of
A) two actin protein strands coiled helically around each other 27 27) Which of the following best describes the term titin?
A) protein that accounts for elasticity of resting muscle 28 28) The region of the sarcomere that always contains thin filaments is the
29 29) At rest, active sites on the actin are blocked by
30 30) The series of membranous channels that surround each myofibril is the
A) sarcoplasmic reticulum 31 31) Which of the following statements about the microscopic anatomy of skeletal muscle fibers is false?
D) The net-like sarcoplasmic reticulum surrounds each myofilament 32 32) All of the following proteins are part of the thin filaments except
33 33) When a skeletal muscle fiber contracts, the
B) zones of overlap get larger. 34 34) Since each myofibril is attached at either end of the muscle fiber, when sarcomeres shorten, the muscle fiber
35 45) In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releases
36 46) Each skeletal muscle fiber is controlled by a motor neuron at a single
C) neuromuscular junction 37 47) The narrow space between the synaptic terminal and the muscle fiber is the
38 48) Active sites on the actin become available for binding after
C) calcium binds to troponin 39 49) Receptors for acetylcholine are located on the
40 50) The action potential is conducted into a skeletal muscle fiber by
41 51) The most important factor in decreasing the intracellular concentration of calcium ion after contraction is
B) active transport of calcium into the sarcoplasmic reticulum 42 52) Which of the following acts as an ATPase during the contraction cycle of muscle?
D) the head portion of the myosin molecule 43 53) When calcium ion binds to troponin,
A) tropomyosin rolls away from the active site 44 54) Which of the following become connected by myosin cross-bridges during muscle contraction?
A) thin filaments and thick filaments 45 55) After death, muscle fibers run out of ATP and calcium begins to leak from the sarcoplasmic reticulum into the sarcoplasm. This results in a condition known as
46 56) In rigor mortis
E) All of the answers are correct 47 57) In a sarcomere, cross-bridge attachment occurs specifically in the
48 58) Physical evidence that supports the sliding filament theory of muscle contraction includes
B) decreased width of the H band during contraction 49 59) Triggering of the muscle action potential occurs after
A) acetylcholine binds to chemically-gated channels in the motor end plate. 50 60) The following is a list of the events that occur during a muscle contraction. What is the correct sequence of these events?
51 61) How would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle?
E) It would have little effect on skeletal muscles C) It would cause muscles to stay contracted 52 62) When acetylcholine binds to receptors at the motor end plate, the sarcolemma becomes
A) more permeable to sodium ions 53 63) The cytoplasm of the neuromuscular terminal contains vesicles filled with molecules of the neurotransmitter
54 64) At what point during excitation contraction coupling does exocytosis play a role?
C) during acetylcholine release from the synaptic terminal 55 65) Which of the following statements about excitation-contraction coupling is incorrect?
A) Calcium ions travel through the transverse tubule 56 66) Synaptic vesicles contain neurotransmitters that are released by ________ when the action potential arrives.
57 67) The muscle weakness of myasthenia gravis results from
B) loss of acetylcholine receptors in the end-plate membrane 58 68) A patient takes a medication that blocks ACh receptors of skeletal muscle fibers. What is this drug's effect on skeletal muscle contraction?
E) reduces the muscle's ability for contraction 59 69) The rapid rise and fall in force produced by a muscle fiber after a single action potential is a(n)
60 70) When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This state of maximum tension is called
61 71) A muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in
62 72) If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This addition of one twitch to another is called
63 73) A single motor neuron together with all the muscle fibers it innervates is called a(n)
64 74) The contraction of a muscle exerts a pull on a bone because muscles attach to bones by
65 75) The increase in muscle tension that is produced by increasing the number of active motor units is called
66 76) The type of contraction in which the muscle fibers do not shorten is called
67 77) A weight-lifter strains to lift a heavy weight and there is no movement of the person's arms holding on to the weight. This type of contraction is called a(n) ________ contraction.
68 78) You try to pick up an object and discover that it is much heavier than you expected. Which process must occur in the muscle to increase tension so you can pick up the object?
69 79) In which of the following would the motor units have the fewest muscle fibers?
C) muscles that control the eyes 70 80) In an isotonic contraction,
A) muscle tension exceeds the load and the muscle lifts the load 71 86) In the liver, during the Cori cycle,
C) glucose is produced from lactic acid 72 87) During the recovery period the body's need for oxygen is increased because
C) additional oxygen is required to restore energy reserves 73 88) A resting muscle generates most of its ATP by
C) aerobic metabolism of fatty acids 74 89) Creatine phosphate
C) acts as an energy reserve in muscle tissue 75 90) During anaerobic glycolysis,
E) All of the answers are correct 76 91) Aerobic metabolism normally provides ________ percent of the ATP demands of a resting muscle cell.
77 92) After heavy exercise, if energy reserves in a muscle are depleted, ________ occurs.
78 93) During the recovery period following exercise, all of the following are true except
C) muscle fibers are unable to contract 79 94) At peak levels of muscle exertion the mitochondria can supply
D) only about one-third of the energy required by the muscle 80 95) Which of the following hormones directly stimulates growth of muscle tissue, leading to increased muscle mass?
81 96) Which of the following would not lead to increased oxygen consumption?
C) increased anaerobic respiration by muscle cells 82 97) Because skeletal muscle contractions demand large quantities of ATP, skeletal muscles have
E) many mitochondria and a rich blood supply 83 98) Decreased blood flow to a muscle could result in all of the following except
C) an increase in intracellular glycogen 84 99) How would an elevated level of thyroid hormone in the body affect skeletal muscles?
C) It would stimulate energy use and heat production 85 100) Heat energy gained from muscle contraction is released by the ________ system.
86 101) The type of muscle fiber that is most resistant to fatigue is the ________ fiber.
87 102) Fast fibers
E) have low resistance to fatigue and quick twitches 88 103) Muscles that move the eyeball have ________ fibers.
89 104) During activities requiring aerobic endurance,
C) most of the muscle's energy is produced in mitochondria 90 105) Fast muscle fibers can adapt to aerobic metabolism by generating more mitochondria in response to
A) repeated, exhaustive stimulation 91 106) Which of the following statements is/are false regarding human muscles?
B) Slow fibers are abundant in the muscles of the hand 92 107) When comparing slow muscle fibers to fast muscle fibers, slow fibers
E) All of the answers are correct 93 108) Large-diameter, densely packed myofibrils, large glycogen reserves, and few mitochondria are characteristics of
94 109) Which of the following types of muscle fibers are best adapted for prolonged contraction such as standing all day?
95 110) Muscular force can be adjusted to match different loads by
E) All of the answers are correct. 96 111) Which of the following statements is false?
C) Skeletal muscle and cardiac muscle stimulation is neural 97 112) The ability of smooth muscle to function over a wide range of lengths is called
98 113) Which of the following is not characteristic of smooth muscle?
A) The striations are due to the orderly arrangement of actin and myosin 99 114) Which of the following is not a function of smooth muscle tissue?
C) forcing blood from the heart into the major arteries 100 1) A(n) ________ can be described as a broad tendinous sheet.
101 2) The protein that is found in the Z line of a sarcomere is called
102 3) The protein that regulates muscle contraction by controlling the availability of active sites on actin is called
103 4) Thin filaments are mostly made of the protein
104 5) Thick filaments are made of the protein
105 6) Stem cells located between the endomysium and sarcolemma that function in the repair of damaged muscle tissue are called
106 7) The complex of a transverse tubule and two adjacent terminal cisternae is known as a
107 8) The structural theory that explains how a muscle fiber contracts is called the ________ theory.
108 9) Communication between axons and muscle fibers occurs at specialized synapses called
E) neuromuscular junctions 109 10) Active sites become exposed when calcium ions bind to
110 11) Cross bridge detachment is caused by ________ binding to the myosin head.
111 12) The sequence of processes that links the action potential to contraction is called
C) excitation-contraction coupling 112 13) An infection by the bacterium Clostridium tetani can cause the disease called
113 14) A single contraction-relaxation cycle in a muscle fiber produces a(n)
114 15) A muscle produces its highest tension when in complete
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