THE MUSCULAR SYSTEM EXAM STUDY GUIDE
98. Two abundant organelles in skeletal muscle are a. cilia and lysosomes b. ATP and glucose c. mitochondria and ATP d. myofibrils and mitochondria
d. myofibrils and mitochondria
93. Which of the following muscles typically operate under voluntary control? cardiac skeletal smooth
skeletal
78.. All muscle cells contain actin and myosin. A. True B. False
true All muscle contraction is based on the interaction between actin and myosin but different types of muscle have different forms of myosin.
29. Select the one INCORRECT statement about skeletal muscles A. An "agonist" opposes or reverses a particular movement B. A muscle's attachment point to a stationary bone is called its "origin". C. A skeletal muscle cell is a "syncytium". D. Muscles that immobilise a bone are called "fi xators".
A. An "agonist" opposes or reverses a particular movement
21What is the name given to one of the units that contract? A. sarcomere B. sarcolemma C. sarcoplasm D. fasciculus
A. sarcomere
51.Muscle tissue has all of the following properties except ________. A. secretion B. extensibility C. excitability D. contractility
A. secretion
73. Curare is a naturally occurring compound that competitively binds to nicotinic acetylcholine receptors on muscle cells. Which of the following symptoms might be seen in a patient who has been exposed to curare? A. Diaphragmatic paralysis B. Cardiac arrest C. Excessive salivation D. Muscle spasticity
A. Diaphragmatic paralysis
68. What is the role of acetylcholine in calcium release? A. Stimulates cellular contraction by opening voltage-gated ion channels B. Stimulates postsynaptic acetylcholine receptors to release intracellular calcium C. Binds to sarcoplasmic reticulum, causing calcium release D. Binds to the T-tubules, causing calcium release
A. Stimulates cellular contraction by opening voltage-gated ion channels
4. During muscle cell contraction, what happens because of Ca ++ binding to troponin? A. The binding site on actin is uncovered. B. Acetylcholine (ACh) is released. C. The cross-bridge disengages from the thin fi lament. D. ATP hydrolyses to ADP.
A. The binding site on actin is uncovered.
74. Which of the following is accurate regarding Type I and Type II muscle fibers? A. Type I fibers store much of their energy as triglycerides, whereas Type II fibers store energy as ATP or creatine phosphate. B. Type I fibers are easily fatigued and are therefore intended for short bursts of activity C. Type I fibers employ anaerobic metabolism, whereas Type II fibers utilize aerobic metabolism D. Type I fibers are white, whereas Type II fibers are red
A. Type I fibers store much of their energy as triglycerides, whereas Type II fibers
25. What is the role of calcium ions in muscle contraction? To A. bind to troponin, thus changing its shape and pulling it away from the actin B. molecule. C. cause the myosin cross-bridge to detach from its binding site. D. cause the action potential to propagate along the sarcolemma. E. bind with ADP during aerobic respiration to produce ATP to provide energy.
A. bind to troponin, thus changing its shape and pulling it away from the actin
44.Which of the following types of muscle tissue contract when excited by their own autorhythmic muscle fibers? A. cardiac muscle B. slow twitch oxidative skeletal muscle C. multi-unit smooth muscle D. fast twitch glycolytic skeletal muscle E. All of these choices are correct.
A. cardiac muscle
2. Smooth muscle is different from skeletal muscle because smooth muscle A. is found in the walls of arteries B. can be voluntarily contracted C. has many nuclei in a cell D. has intercalated discs between cells
A. is found in the walls of arteries
58.A neuromuscular junction (NMJ) A. is the synapse of a motor neuron with a muscle fiber. B. includes the synaptic end bulbs of the muscle fiber. C. includes the motor endplates of the motor neuron. D. uses Na+ as a neurotransmitter. E. All of the above are correct.
A. is the synapse of a motor neuron with a muscle fiber.
12. Which is the largest of the structures in a muscle fi bre? A. myofibril B. myofilament C. myosin D. myopic
A. myofibril
52.The contractile organelles of a skeletal muscle fiber are thread-like structures called A. myofibrils. B. myoglobin. C. mitochondria. D. Z discs.
A. myofibrils.
63.The oxygen-binding protein found in muscle cells is ________. A. myoglobin B. hemoglobin C. ATP D. immunoglobin
A. myoglobin
6. Which of the following is the smallest structure within a muscle fiber? A. myosin B. myofi lament C. myofi bril D. sarcomere
A. myosin
3. All of the following structures are part of a muscle cell except one. Which one? A. sarcoma B. sarcolemma C. sarcoplasm D. sarcoplasmic reticulum
A. sarcoma
26.Which of the following describes skeletal muscle? A. striated, voluntary, multinucleate, individually named. B. striated, branched, uninucleate, involuntary. C. not striated, uninucleate, voluntary, individually named. D. not striated, multinucleate, involuntary, with intercalated discs.
A. striated, voluntary, multinucleate, individually named.
48.What produces the striations of a skeletal muscle cell? A. the arrangement of myofilaments B. the sarcoplasmic reticulum C. a difference in the thickness of the sarcolemma D. the T tubules
A. the arrangement of myofilaments
32. What is the role of Ca ++ in the contraction of a muscle cell? A. Ca ++ binds to troponin to change its shape which reveals actin's binding site. B. Ca ++ attaches to the binding site of actin C. Ca ++ detaches from ATP as it forms ADP D. Ca ++ causes the myosin head to detach from the binding site of actin
Answer is A: Actin's binding site is covered until calcium causes it to be exposed.
14. Which statement below best describes the role of Ca ++ in muscle contraction? A. Ca ++ binds to troponin, thereby changing its shape to expose the binding site. B. Ca ++ causes ADP and inorganic phosphate to detach from the myosin crossbridge. C. Ca ++ attaches to the myosin head, causing it to disengage from its binding site. D. Ca ++ crosses the sarcolemma from the axon terminal which allows the E. action potential to propagate along the sarcolemma
Answer is A: Ca attaches to troponin causing a shape change which shifts theattached tropomyosin away from binding sites of actin
36 When a muscle contracts, exactly what structure gets shorter? A. the fascicles of a muscle B. the myosin molecules of a myofilament C. the actin molecules of a myofilament D. the sarcomeres of a myofibril
Answer is D: The length of the sarcomeres decreases.
35. What binds to troponin causing it to expose the binding site on actin to enable muscle cell contraction? A. Ca ++ (calcium) B. ACh (acetylcholine) C. PO 4 D. 2− (phosphate) E. ADP (adenosine diphosphate)
Answer is A: Troponin has a binding site for calcium.
24. Which statement about thick or thin myofi laments is CORRECT? A. Thick myofi laments contain the three proteins myosin, tropomyosin and B. troponin. C. Thin myofi laments contain the three proteins actin, tropomyosin and D. troponin. E. Thick myofi laments contain about 300 myosin molecules each of which has F. a binding site for a cross bridge. G. Thin myofi laments contain about 300 myosin molecules each of which has H. a cross bridge.
Answer is B: Thin myofi laments contain these three proteins. Choices C & D are wrong as myosin has a cross-bridge rather than a binding site.
0. Which of the following muscle structures is the largest? A. sarcomere B. fascicle C. myofi bril D. muscle fi bre
Answer is B: B. fascicle A muscle fascicle is a bundle of muscle fi bres (cells). Choice A &B are smaller than a cell. A skeletal muscle fiber (cell) consists of many sections (units) which contract.
28. Which of these events is necessary for the contraction of a muscle cell? A. the shortening of myosin molecules. B. the hydrolysis of ATP to ADP & HPO 4 2− in the myosin cross-bridge. C. Ca 2+ binding to tropomyosin causing it to change shape. D. the movement of Ca 2+ from the sarcoplasm into the sarcoplasmic reticulum.
Answer is B: B. the hydrolysis of ATP to ADP & HPO 4 The hydrolysis of ATP energises the cross-bridge. (myosin molecules do not get shorter; calcium binds to troponin, not tropomyosin; calcium returns to the SR after contraction).
38. What does aerobic respiration refer to? A. glycolysis in the cytoplasm in the absence of oxygen. B. oxidative phosphorylation in the mitochondria in the presence of oxygen. C. glycolysis in the liver in the presence of oxygen D. gluconeogenesis in the liver in the absence of oxygen
Answer is B: Respiration occurs in the mitochondria of a cell. The term aerobic refers to the presence of oxygen.
13.Which protein(s) are found in thin myofilaments? A. actin B. actin and tropomyosin C. actin, tropomyosin, and troponin D. actin, myosin, tropomyosin, and troponin
Answer is C: Actin is the major component of a thin fi lament. Tropomyosincovers the biding site, while troponin provides the mechanism for removingtropomyosin from the binding site.
30. Which of the following groupings of muscle type and their characteristics is INCORRECT? A. skeletal, striated, voluntary B. smooth, visceral, involuntary C. cardiac, striated, voluntary D. skeletal, striated, syncytium
Answer is C: cardiac muscle is not voluntary.
31. The part of a skeletal muscle cell that is able to contract is called A. sarcoplasm B. sarcolemma C. sarcomere D. sarcoplasmic reticulum
Answer is C: sarcomeres contain myofi laments that slide past each other as the sarcomere contracts.
23. Which of these events is necessary for the contraction of a muscle cell? A. the shortening of myofi laments. B. the conversion of ADP & HPO 4 C. 2− to ATP in the cross-bridge. D. Ca 2+ binding to troponin causing it to change shape. E. the movement of ACh from the sarcolemma to the axon terminal.
Answer is C: the binding of calcium is essential. (choice A is wrong as myofi laments don't shorten - they slide past each other. Choices B & D are the reverse of what actually happens).
17. What is the source of most of the energy needed by muscles for physical activity that continues for longer than 30 or 40 minutes.? A. ATP stored in muscle fi bres. B. glycolysis of glucose in the cell cytoplasm C. ATP produced from creatine phosphate stored in muscle fi bres D. aerobic respiration of pyruvic acid in mitochondria
Answer is D: Choice A lasts for a few seconds only. Choice B can provideenergy for a couple of minutes. Choice C can provide energy for vigorousactivity lasting about 15 seconds
33. The energy for muscle contraction is derived from the mechanisms below EXCEPT for one. Which one is NOT a method of producing ATP? A. anaerobic glycolysis. B. aerobic respiration. C. direct phosphorylation of ADP by creatinine phosphate. D. anaerobic digestion of lactic acid.
Answer is D: ATP is not produced from lactic acid - lactic acid is produced from pyruvic acid after glucose is anaerobically lysed into ATP and pyruvic acid.
22. The neurotransmitter that causes an action potential to occur in a muscle cell membrane is called: A. inorganic phosphate (HPO 42− ) B. adenosine diphosphate (ADP) C. calcium (Ca ++ ) D. acetylcholine (ACh)
Answer is D: Acetylcholine is the neurotransmitter. All somatic motor neurons release ACh at their synapses with skeletal muscle fi bres.
34.What is the source of the ATP used by muscles for vigorous activity that may last for 10 to 15 seconds? A. glycolysis of glucose in the cell cytoplasm forms ATP. B. the ATP that is stored in muscle cells as ATP. C. aerobic respiration in the mitochondria produces the ATP D. creatinine phosphate in muscle and ADP react to form the required ATP.
Answer is D: Creatinine phosphate is used to "recharge" the ADP that forms from ATP when the cross-bridge is energized.
79. The muscle fibres of skeletal muscle are electrically coupled so that one nerve fibre can control the activity of several muscle fibers. A. True B. False
Answer is False Skeletal muscle fibers act independently of each other unlike cardiac and smooth muscle cell which are linked by gap junction
77. Skeletal muscle has a system of T-tubules while smooth muscle does not. A. True B. False
Answer is True All muscle contraction is based on the interaction between actin and myosin, but different types of muscle have different forms of myosin
56. A muscle that opposes, or reverses, a particular movement is a(n) ________. A. agonist B. antagonist C. fixator D. synergist
B. antagonist
42.Which of the following statements is most accurate? A. Myofilaments slide during isometric contractions. B. Muscle tension remains relatively constant during isotonic contraction. C. The I band lengthens during isotonic contraction. D. T tubules may be sliding during isotonic contraction.
B. *Muscle tension remains relatively constant during isotonic contraction.
5.Which of the following muscle cell structures is the longest? A. A myofi lament B. A myofi bril C. A sarcomere D. A troponin molecule
B. A myofi bril
19. What is the role of Ca ++ in muscle contraction? A. Ca causes an action potential to travel along the sarcolemma B. Ca binds to troponin changing its shape. C. Ca attaches to the binding site of myosin, energizing it. D. Ca engages with the binding site of actin causing the power stroke
B. Ca binds to troponin changing its shape
83 Which of the following statements concerning cardiac muscle is incorrect? A. The force of contraction is increased by circulating adrenaline correct B. Heart muscle contracts in response to action potentials in the autonomic nerve fibers incorrect C. The action potential is about 10-20 times as long as that of skeletal muscle correct D. All of the Ca2+ required for contraction enters cardiac myocyte from ECF and the sarcoplasmic reticulum
B. Heart muscle contracts in response to action potentials in the autonomic nerve fibers incorrect
81. The maximum power that can be developed by a skeletal muscle A. Is dependent of the initial length of the muscle incorrect B. Occurs with an isometric contraction incorrect C. Occurs when the muscle is moving a load at about one third of its maximum rate of shortening correct D. Depends on the load being moved by the muscle correct
B. Occurs with an isometric contraction incorrect
76. Which of the following statements concerning the structure of muscle tissue is not correct? A. Skeletal muscle and cardiac muscle are both striated B. Smooth muscle cells have no striations as they lack myosin filaments C. The spread of excitation through a skeletal muscle fiber is brought about by a system of T-tubules. D. The myofibrils of skeletal muscle are surrounded by the sarcoplasmic reticulum
B. Smooth muscle cells have no striations as they lack myosin filaments
75. Which of the following is NOT innervated by the autonomic nervous system? A. Branching muscle cell B. Striated skeletal muscle cell C. Myocardial cell D. Intestinal muscle cell
B. Striated skeletal muscle cell
45.After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction? A. the action potential stops going down the overloaded T tubules B. acetylcholinesterase destroying the ACh C. calcium ions returning to the terminal cisternae D. the tropomyosin blocking the myosin once full contraction is achieved
B. acetylcholinesterase destroying the ACh
27. Which list is in the correct order of DECREASING size? A. muscle fi bre, sarcomere, myofilament, myofi bril. B. muscle, fasciculus, muscle fi bre, myofi bril. C. sarcomere, fasciculus, myofi bril, myofi lament. D. muscle, muscle fibre, myosin, myofibril.
B. muscle, fasciculus, muscle fi bre, myofi bril
47.When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods? A. relaxation period B. refractory period C. fatigue period D. latent period
B. refractory period
11. Which term is given to the unit of a myofibril that contracts? A. sarcoplasm B. sarcomere C. sarcolemma D. sarcoplasmic reticulum
B. sarcomere
95. Myoglobin ________. A. is a protein involved in the direct phosphorylation of ADP B. stores oxygen in muscle cells C. breaks down glycogen D. stores oxygen in muscle cells
B. stores oxygen in muscle cells
71.What is an aponeurosis? A. A segment of muscle that is not attached to bone B. An area of smooth muscle in the abdomen C. A large, flat tendon that anchors muscle D. A group of neurons that innervate striated muscle cells
C. A large, flat tendon that anchors muscle
1. Of the events that lead to myofilaments sliding over each other, which of the following happens first? A. The myosin head engages with the binding site on actin B. Troponin changes shape and pulls on tropomyosin C. Calcium ions enter the cell cytoplasm D. ATP is hydrolyzed to ADP and inorganic phosphate
C. Calcium ions enter the cell cytoplasm
92. Skeletal muscle cells require a great amount of energy. Which organelles do you expect to find in abundance in skeletal muscle cell? A. Golgi bodies. B. Mitochondria. C. Nuclei. D. Striations
C. Nuclei.
89. striations, cylindrical cells, and multiple nuclei are observed in ________. A. Smooth muscle only. B. Skeletal and cardiac muscles. C. Skeletal muscle only. D. Cardiac muscle only
C. Skeletal muscle only.
67.What is the role of tropomyosin in muscle contraction? A. To release troponin from tropomyosin, allowing myosin to bind to the actin filament B. To release calcium from the sarcoplasmic reticulum C. To prevent myosin from continuing to slide up the actin filament D. To aid in myosin 'cocking' on the actin filament
C. To prevent myosin from continuing to slide up the actin filament
8. What is a "sarcomere"? A. a cancer of connective tissue B. the cytoplasm of a muscle cell C. a section of a myofilament. D. the plasma membrane of a muscle cell.
C. a section of a myofilament
10. By which term is a muscle that opposes or reverses a particular movement called? A. agonist B. synergist C. antagonist D. fixator
C. antagonist
16.What causes the myosin binding site of an actin molecule to be exposed? A. ATP attaching to the myosin cross-bridge B. a nerve impulse reaching the motor end plate of a motor nerve. C. calcium ions attaching to troponin D. acetylcholine crossing the neuromuscular junction
C. calcium ions attaching to troponin
65.This is the property of muscle that gives it the ability to stretch without damage. A. electrical excitability B. contractility C. extensibility D. elasticity E. thermogenesis
C. extensibility
57. An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is ________. A. hydrolysis B. the electron transport chain C. glycolysis D. the citric acid cycle
C. glycolysis
55 Muscular atrophies A. is in increase in muscle mass due to increased numbers of myofibrils. B. is an increase in muscle mass due to increased numbers of myofibers. C. is a decrease in muscle mass due to loss of myofibrils. D. is the result of overuse of muscles. E. is always reversible, no matter what the cause.
C. is a decrease in muscle mass due to loss of myofibrils.
15. What characteristic of a smooth muscle cell distinguishes it from cardiac and from skeletal muscle? A. being branched B. being under involuntary control C. lack of striations D. being uninucleate
C. lack of striations
54. Rigor mortis occurs because ________. A. proteins are beginning to break down, thus preventing a flow of calcium ions B. sodium ions leak into the muscle causing continued contractions C. no ATP is available to release attached actin and myosin molecules D. the cells are dead
C. no ATP is available to release attached actin and myosin molecules
Skeletal muscle cells have all of the following characteristics EXCEPT one. Which one? A. a neuromuscular junction crossed by ACh (acetyl choline) B. invaginations of sarcolemma called "T tubules". C. they are branched D. they are striated
C. they are branched
66.Which of the following is the dark band seen on myofibrils? A. H Band B. Z Line C. I Band D. A Band
D. A Band
43.Which of the following regions of a sarcomere contain thin filaments? A. I band B. A band C. H zone D. Both I band and A band. E. All of these answer choices are correct.
D. Both I band and A band.
7. Which of the events below is the FIRST to occur prior to a muscle cell contracting? A. ATP binds to myosin. B. ADP detaches from myosin. C. the active site on actin is exposed. D. Ca ++ is released from the sarcoplasmic reticulum
D. Ca ++ is released from the sarcoplasmic reticulum
2. All the following is correct facts about of Botulinum toxin except? A. The botulinum toxin, is produced by the bacteria Clostridium botulinum B. The botulinum toxin locks the release of ACh contained within the synaptic end bulb. C. The botulinum toxin symptoms are paralyzing the victim, stopping respiration, and leading to death. D. Cause blocking ACh receptors within the motor end plate of the muscle fiber.
D. Cause blocking ACh receptors within the motor end plate of the muscle fiber.
69.. Which of the following correctly identifies muscle components in order from largest to smallest? A. Muscle fiber, fasciculus, myofibril B. Sarcolemma, sarcoplasm, fasciculus C. Fasciculus, muscle fiber, myofibril D. Fasciculus, muscle bundle, myofibril
D. Fasciculus, muscle bundle, myofibril
90. The cells of muscles, myocytes, develop from ________. A. Endoderm. B. Chondrocytes. C. Fibrocytes. D. Myoblasts
D. Myoblasts
72. We would expect to find smooth muscle in all of the following EXCEPT: A. Pulmonary circulatory tissue B. Esophagus C. Small intestine D. Myocardial tissue
D. Myocardial tissue
70. The space between two Z lines constitutes the: A. Sarcolemma B. Sarcophagus C. Sarcoplasm D. Sarcomere
D. Sarcomere
84.Which of the following statements concerning the contraction of smooth muscle are correct? A. Smooth muscles are innervated by autonomic nerves B. Some smooth muscles may contract without an action potential C. Smooth muscle fibers have no specialized neuromuscular junctions D. The contraction of smooth muscle is regulated by calcium in the same manner as cardiac muscle.
D. The contraction of smooth muscle is regulated by calcium in the same manner as cardiac muscle.
82. The action potential of cardiac muscle fibers is initiated by action potentials in sympathetic nerve fibers. A. True B. False
False The myocytes of the SA node generate spontaneous action potentials that set the heart rate but the heart rate is increased by stimulation of the cardiac sympathetic nerves.
80.. Which of the following statements concerning the role of Ca2+ in the contraction of skeletal muscle is correct? A. The calcium for skeletal muscle contraction is derived from the sarcoplasmic reticulum. B. Ca2+ released from the sarcoplasmic reticulum is essential for the contraction of skeletal muscle C. A rise in intracellular Ca2+ allows actin to interact with myosin D. The tension of a skeletal muscle fiber is partly regulated by G proteins.
D. The tension of a skeletal muscle fiber is partly regulated by G proteins.
46.Which of the following correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction? A. sarcolemma, axon of neuron, T tubules B. T tubules, sarcolemma, myofilament C. muscle fiber, axon of neuron, myofibrils D. axon of neuron, sarcolemma, T tubules E. myofibrils, myofilaments, mitochondria
D. axon of neuron, sarcolemma, T tubules
49.A period of sustained skeletal muscle contraction in which individual twitches cannot be detected is called A. unfused tetanus. B. muscle atrophy. C. flaccidity. D. fused tetanus.
D. fused tetanus.
53 Fatigued muscle cells that recover rapidly are the products of ________. A. slow exercise of short duration B. slow exercise of long duration C. intense exercise of long duration D. intense exercise of short duration
D. intense exercise of short duration
9. Smooth muscle cells may be described by which of the following? A. striated, voluntary, multinucleate B. not striated, voluntary, multinucleate C. striated, involuntary, uninucleate D. not striated, involuntary, uninucleate
D. not striated, involuntary, uninucleate
31. Microscopically, muscle fi bres contain parallel myofi brils. What are the units joined end to end within a myofibril called? A: A. myofilament B. motor unit C. myosin D. sarcomere
D. sarcomere
39.Which of the following proteins is used to reinforce the sarcolemma and to help transmit the tension generated by the sarcomeres to the tendons? A. troponin B. tropomyosin C. myosin D. actin E. *dystrophin
E. *dystrophin
62.After several visits to the gym and serious "iron pumping" (strength training) you notice that your biceps have enlarged. Which one of the following has happened to your muscles? A. atrophy B. dystrophy C. hyperplasia D. heterotrophy E. Hypertrophy
E. Hypertrophy
61Which of the following is NOT a major function of muscle tissue? A. moving blood throughout the body B. generating heat through contractions C. stabilizing the movement of joints D. promoting movement of body structures E. Production of Vitamins.
E. Production of Vitamins.
64.Which of the following statements is true? A. Striated muscle cells are long and cylindrical with many nuclei. B. Cardiac muscle cells are found in the heart and large blood vessels. C. Smooth muscle cells have T tubules. D. Cardiac muscle cells have many nuclei. E. Striated muscle cells are long and cylindrical with many nuclei.
E. Striated muscle cells are long and cylindrical with many nuclei.
61.The term aponeurosis refers to ________. A. the rough endoplasmic reticulum B. a sheetlike indirect attachment to a skeletal element C. the bands of myofibrils D. the tropomyosin-troponin complex E. a sheetlike indirect attachment to a skeletal element
E. a sheetlike indirect attachment to a skeletal element
60.What is the most distinguishing characteristic of muscle tissue? A. the ability to transform chemical energy into mechanical energy B. the design of the fibers C. the diversity of activity of muscle tissue D. the ability to respond to nervous stimulation E. the ability to transform chemical energy into mechanical energy
E. the ability to transform chemical energy into mechanical energy
50A brief contraction of all muscle fibers in a motor unit in response to a single action potential moving down the somatic motor neuron is known as A. isometric contraction. B. isotonic contraction. C. tetany. D. refractory period. E. twitch contraction.
E. twitch contraction.
1. Which of the following is the most appropriate treatment? a. Botulinum antitoxin b. Amphotericin B c. Staphylococcus aureus enterotoxin toxoid d. Ampicillin
a. Botulinum antitoxin
87. Which of the following muscle tissues are striated? I. skeletal II. cardiac III. smooth a. I only b. III only c. I and III
a. I only
96. The membrane that carries the muscle fiber's electrical signal from the surface to the fiber's interior is the a. t-tubule (transverse tubule) b. SR (sarcoplasmic reticulum) c. CM (cell membrane) d. post-synaptic membrane
a. t-tubule (transverse tubule)
94.. Skeletal muscles are bound to surrounding tissues and other muscles with a type of connective tissues called a. tendon b. endomysium c. ligament d. perimysium e. fascia
a. tendon
86. Name the cellular unit in muscle tissue. a. Filament b. Myofibril c. Fiber d. Motor cell e. Fasciculus
b. Myofibril ( NOT SURE IF ITS SOCOMERE)
85. Why do your muscles shiver when you're cold? a. To prevent paralysis b. To generate heat c. To improve elasticity d. To increase excitability
b. To generate heat
100. Muscle fascicles are surrounded by a. epimysium b. perimysium c. endomysium d. fascia e. tendon
b. perimysium
97.The mineral released from the _______into a fiber that activates _______ to cause muscle contraction is_______. a. t-tubules, ATP, Na+ b. SR, DNA, Ca+2 c. SR, ATP, Ca+2 d. t-tubules, DNA, Ca+2 e. SR, ATP, K+
c. SR, ATP, Ca+2
95. The neurotransmitter sending chemical signals at neuromuscular junctions of skeletal muscle is a. actin b. myosin c. troponin d. acetylcholine e. cholinesterase
d. acetylcholine
99. The hypertrophy of muscles is due to a. increased numbers of myofibrils and the increased amount of connective tissue in the muscle b. increased numbers of fibers inside the muscle c. increased numbers of both fibers and myofibrils inside the muscle d. increased storage of glucose, myoglobin, ATP and creatine phosphate in the muscle
d. increased storage of glucose, myoglobin, ATP and creatine phosphate in the muscle
88. Intercalated discs a. anchor skeletal muscle fibers to one another. b. play a role in moving electrical impulses through the heart. c. are found only in the muscles of the back. d. overlap to cause contraction.
d. overlap to cause contraction