Chapter 11 Muscle Tissue
55) Heat energy produced from muscle contraction is released through the ________ system. A) Integumentary B) respiratory C) cardiovascular D) urinary E) digestive
A) Integumentary
23) Cross-bridges are portions of A) Actin molecules. B) Myosin molecules. C) Troponin molecules. D) Tropomyosin molecules. E) Calcium ions.
B) Myosin molecules. Cocked myosin binds to an exposed active cite forming a cross bridge between myosin and actin
4) Nerves and blood vessels that service the muscle fibers are located in the connective tissues of the A) Endomysium. B) Perimysium. C) Sarcolemma. D) Sarcomere. E) Myofibrils.
B) Perimysium. Bundles muscle fibers (fasicles) A) Endomysium. Surrounds each muscle fiber contains nerves and blood vessels C) Sarcolemma. Plastma membrane of a muscle fiber D) Sarcomere. Functional contractile unite of a muscle fiber E) Myofibrils. A bundle of microfilaments (myfilaments)
5) The delicate connective tissue that surrounds the skeletal muscle fibers and ties adjacent muscle fibers together is the A) Endomysium. B) Perimysium. C) Epimysium. D) Superficial fascia. E) Periosteum.
B) Perimysium. Bundles muscle fibers (fasicles) A) Endomysium. Thin sleeve of loose c.t. that surrounds each muscle fiber C) Epimysium. Surrounds the entire muscle and then grades into fascia
13) The functional unit of a skeletal muscle fiber is the A) Sarcolemma. B) Sarcomere. C) Sarcoplasmic reticulum. D) Myofibril. E) Myofilament.
B) Sarcomere.
62) Skeletal muscle contracts only under stimulation from A) The sympathetic nervous system. B) The parasympathetic nervous system. C) The central nervous system. D) all of the above E) none of the above
C) The central nervous system.
81) When contraction occurs, A) The H and I bands get smaller. B) The width of the A band remains constant. C) The Z lines move closer together. D) A, B, and C E) none of the above
D) A, B, and C A) The H and I bands get smaller. B) The width of the A band remains constant. C) The Z lines move closer together.
64) The pull called tension is a (n) ________ force. A) Passive B) Assertive C) Aggressive D) Active E) all of the above
D) Active
31) In response to action potentials arriving from the transverse tubules, the sarcoplasmic reticulum releases ________. A) Acetylcholine. B) Sodium ions. C) Potassium ions. D) Calcium ions E) Hydrogen ions.
D) Calcium ions
21) The sarcoplasmic reticulum stores A) Oxygen. B) Glycogen. C) ATP. D) Calcium ions. E) Glucose.
D) Calcium ions. A) Oxygen. Reserved in myoglobin B) Glycogen. Starch-like carbohydrate
84) Increased oxygen consumption would accompany all of the following, except A) Increased heat production. B) Increased conversion of lactate to glucose. C) Increased aerobic respiration by muscle cells. D) Decreased ATP use. E) Increased muscle activity.
D) Decreased ATP use.
63) When a skeletal muscle fiber contracts, A) The H zones and I bands get smaller. B) The zones of overlap get larger. C) The Z lines get closer together. D) The width of the A band gets constant. E) all of the above
E) all of the above
82) Which of the following muscles would produce the greater tension? A) a muscle with 20 motor units active B) a muscle with 10 motor units active
A) a muscle with 20 motor units active
52) contraction that utilize anaerobic ATP production A) require maximal contraction of muscles for short periods of time B) do not use ATP very quickly C) rely on slow muscle fibers D) do not rely on the energy reserve of creatine phosphate
A) require maximal contraction of muscles for short periods of time
60) At each end of the muscle, the collagen fibers of the epimysium, perimysium, and endomysium come together to form either a bundle known as a ________, or a broad sheet called an aponeurosis. A) tendon B) satellite cells C) joint D) fascicle E) none of the above
A) tendon
20) Each thin filament consists of A) A pair of protein strands wound together. B) Chains of myosin molecules. C) 6 molecules coiled into a helical structure. D) A rod-shaped structure with "heads" projecting from each end. E) A double strand of myosin molecules.
A) A pair of protein strands wound together.
39) A muscle producing peak tension with rapid cycles of contraction and relaxation is said to be in A) Incomplete tetanus. B) Complete tetanus. C) Treppe. D) Wave summation. E) Recruitment.
A) Incomplete tetanus. (rapid cycles of relaxation and contraction) B) Complete tetanus. (no relaxation phase) C) Treppe. (Second stimulation immediately after the relaxation phase results in higher maximum tension) D) Wave summation. (Wave summation is addition of one twitch to another)
78) When acetylcholine binds to receptors at the motor end plate, the muscle membrane becomes A) More permeable to sodium ions. B) Less permeable to sodium ions. C) More permeable to potassium ions. D) Less permeable to potassium ions. E) Repolarized.
A) More permeable to sodium ions.
10) The cell membrane of skeletal muscle is called the A) Sarcolemma. B) Sarcomere. C) Sarcosome. D) Sarcoplasmic reticulum. E) Sarcoplasm.
A) Sarcolemma. D) Sarcoplasmic reticulum. Forms a network around each myofibril
57) Which of the following is not characteristic of smooth muscle? A) Smooth muscle connective tissue forms tendons and aponeuroses. B) Neurons that innervate smooth muscles are under involuntary control. C) Smooth muscles are uninucleate. D) Smooth muscles do not contain sarcomeres. E) The thin filaments of smooth muscle fibers are attached to dense bodies.
A) Smooth muscle connective tissue forms tendons and aponeuroses. D) Smooth muscles do not contain sarcomeres. (not arranged in sarcomeres) B) Neurons that innervate smooth muscles are under involuntary control. (true) C) Smooth muscles are uninucleate. (single oval, centrally located nucleus) E) The thin filaments of smooth muscle fibers are attached to dense bodies. (true)
33) When calcium ion binds to troponin A) Tropomyosin moves out of the groove between the actin molecules B) Actin sites on the myosin are exposed C) Actin heads will bind to myosin D) Muscle relaxation occurs E) Myosin shortens
A) Tropomyosin moves out of the groove between the actin molecules (t/t complex changes shape and sinks deeper into the groove of the thin filament) B) Actin sites on the myosin are exposed (there are no actin sites on the myosin and myosin doesn't change exposure) C) Actin heads will bind to myosin (actin doesn't have heads, myosin does) D) Muscle relaxation occurs (these steps happen during contraction preparation) E) Myosin shortens (it doesn't shorten, the actin moves across it)
37) The type of contraction represented by a single stimulus/contraction/relaxation sequence is a(n) A) Twitch. B) Incomplete tetanus. C) Complete tetanus. D) Summation. E) Incomplete summation.
A) Twitch. B) Incomplete tetanus. (high stimulus frequency, each stimulus arriving before the previous twitch is over) C) Complete tetanus. (higher stimulus frequency, prolonged muscle contraction)
16) Thin filaments at either end of the sarcomere are attached to the A) Z line. B) M line. C) H band. D) A band. E) I band.
A) Z line.
74) Which of the following is greater? A) the concentration of calcium ion in the sarcoplasmic reticulum of a resting muscle B) the concentration of calcium ion in the sarcoplasm of a resting muscle
A) the concentration of calcium ion in the sarcoplasmic reticulum of a resting muscle
72) Because skeletal muscle contractions demand large quantities of ATP, skeletal muscles have A) A rich nerve supply. B) A rich vascular supply C) Very few mitochondria. D) Little need for oxygen. E) A large concentration of tissue hemoglobin.
B) A rich vascular supply
22) The skeletal muscle complex known as the triad consists of A) Actin, myosin, and filaments. B) A transverse tubule and terminal cisternae. C) Filaments, myofibrils, and sarcomeres. D) A bands, H bands, and I bands. E) Actin, myosin, and sarcomeres.
B) A transverse tubule and terminal cisternae.
34) The most important factor in decreasing the intracellular concentration of calcium ion after contraction is A) Active transport of calcium across the sarcolemma. B) Active transport of calcium into the sarcoplasmic reticulum. C) Active transport of calcium into the synaptic cleft. D) Diffusion of calcium out of the cell. E) Diffusion of calcium into the sarcoplasmic reticulum.
B) Active transport of calcium into the sarcoplasmic reticulum. (active transport pumps in the SR begin to pump calcium back into the cisternae) A) Active transport of calcium across the sarcolemma. (this would be moving out of the cell) C) Active transport of calcium into the synaptic cleft. (no) D) Diffusion of calcium out of the cell. (Calcium ions are pumped into the SR and are not replaced) E) Diffusion of calcium into the sarcoplasmic reticulum. (it doesn't diffuse it is actively transported)
41) A muscle that is stimulated so frequently that the relaxation phase is completely eliminated is said to exhibit A) Incomplete tetanus. B) Complete tetanus. C) Treppe. D) Wave summation. E) Recruitment.
B) Complete tetanus.
70) Physical evidence that supports the sliding filament theory of muscle contraction includes A) Increased width of the H band during contraction. B) Decreased distance between Z lines during contraction. C) Increased width of the I band during contraction. D) Decreased width of the A band during contraction. E) An increased distance between Z lines during contraction.
B) Decreased distance between Z lines during contraction.
7) Muscle fibers differ from "typical cells" in that muscle fibers A) Lack a cell membrane. B) Have many nuclei. C) Are very small. D) Lack mitochondria. E) both B and C
B) Have many nuclei. D) Lack mitochondria. Mitochondria are packed into the spaces between myfibrils A) Lack a cell membrane. sarcolemna
15) In a sarcomere, thick filaments are linked by the A) Z line. B) M line. C) H band. D) A band. E) I band.
B) M line. Transverse protein complex that links thick filaments to each other A) Z line. Anchors thin and elastic filaments C) H band. Area where thin filaments don't reach D) A band. Thick filaments only E) I band. Thin filament bisected by the Z line
28) Receptors for acetylcholine are located on the A) Synaptic knob. B) Motor end plate. C) Sarcomere. D) Synaptic cleft. E) Transverse tubule.
B) Motor end plate.
12) The series of membranous channels that surround each myofibril is the A) Sarcolemma. B) Sarcoplasmic reticulum. C) Myolemma. D) Sarcoplasm. E) Transverse tubule.
B) Sarcoplasmic reticulum. Forms a network around each myofibril D) Sarcoplasm. goo E) Transverse tubule. Infoldings of sarcolema which penetrate the cell.
51) The type of muscle fiber that is most resistant to fatigue is the ________ fiber. A) Fast. B) Slow. C) Anaerobic. D) Intermediate. E) high-density.
B) Slow.
6) The bundle of collagen fibers at the end of a skeletal muscle that attaches the muscle to bone is called a(n) A) Fascicle. B) Tendon. C) Ligament. D) Epimysium. E) Myofibril.
B) Tendon. Collagenous band or cord associated with a muscle, usually attaching it to bone and transferring musclular tension to it. A) Fascicle. Bundle of muscle fibers C) Ligament. Binds organ to organ or bone to bone. Holds things in place E) Myofibril. =muscle cell = muscle fiber
67) In an isotonic contraction, A) Muscle tension exceeds the resistance and the muscle shortens. B) Tension rises and the skeletal muscle length changes. C) The peak tension developed is less than the resistance. D) The muscle as a whole does not change length. E) all of the above
B) Tension rises and the skeletal muscle length changes. A) Muscle tension exceeds the resistance and the muscle shortens. (concentric, in eccentric it would elongate) D) The muscle as a whole does not change length. (isometric)
75) When myosin cross-bridges bind to the active sites on actin, A) ATP is hydrolyzed. B) They pivot toward the M line. C) The sarcomere strengthens. D) Muscle relaxation occurs. E) The I band moves closer to the Z line.
B) They pivot toward the M line.
81) Which of the following muscles would contract more forcefully? A) a muscle receiving 5 action potentials per second B) a muscle receiving 10 to 15 action potentials per second
B) a muscle receiving 10 to 15 action potentials per second
94) During muscle contraction, myosin cross bridges attach to active sites of: A) myosin filaments B) actin filaments C) Z lines D) thick filaments E) the H zone
B) actin filaments
47) When energy reserves in a muscle are exhausted and lactic acid levels increase, ________ occurs. A) an oxygen debt B) fatigue C) treppe D) tetanus E) atrophy
B) fatigue
17) The area of the sarcomere containing the thick filaments is the A) Z line. B) M line. C) A band. D) I band.
C) A band.
65) In the neurons that innervate skeletal muscles, the cytoplasm of the synaptic terminal contains mitochondria and vesicles filled with molecules of the neurotransmitter A) Epinephrine. B) Norepinephrine. C) Acetylcholine. D) Antidiuretic hormone. E) all of the above
C) Acetylcholine.
45) Creatine phosphate A) Is produced by the process of anaerobic respiration. B) Can replace ATP in binding to myosin molecules during contraction. C) Acts as an energy reserve in muscle tissue. D) Is only formed during strenuous exercise. E) Cannot transfer its phosphate group to ADP.
C) Acts as an energy reserve in muscle tissue.
48) During the recovery period following exercise, all of the following are true, except A) Lactic acid is removed from muscle cells. B) The muscle actively produces ATP. C) Muscle fibers remain contracted D) Oxygen is consumed. E) Heat is generated.
C) Muscle fibers remain contracted
49) During the recovery period the body's need for oxygen is increased because A) Muscle cells are producing energy anaerobically. B) The individual is panting. C) Additional oxygen is required to metabolize the lactic acid produced during exercise. D) The liver requires more oxygen to produce lactic acid. E) The muscles are not producing ATP.
C) Additional oxygen is required to metabolize the lactic acid produced during exercise. D) The liver requires more oxygen to produce lactic acid. (liver is converting lactic acid into pyruvatic acid)
44) A resting muscle generates most of its ATP by A) Conversion of creatine phosphate. B) Anaerobic respiration. C) Aerobic respiration. D) Glycogenolysis. E) The tricarboxylic acid cycle.
C) Aerobic respiration. (of fatty acids)
83) Decreased blood flow to a muscle could result in all of the following, except A) Fatigue. B) An oxygen debt. C) An increase in intracellular glycogen. D) A shift to more anaerobic glycolysis in the muscle. E) An increase in intracellular lactate.
C) An increase in intracellular glycogen.
30) Active sites on the actin become available for binding when A) Actin binds to troponin. B) Troponin binds to tropomyosin. C) Calcium binds to troponin. D) Calcium binds to tropomyosin. E) Myosin binds to troponin.
C) Calcium binds to troponin.
69) Large diameter, densely packed myofibrils, large glycogen reserves, and few mitochondria are characteristics of A) Slow fibers. B) Intermediate fibers. C) Fast fibers. D) Red muscles. E) Fatty muscles.
C) Fast fibers. A) Slow fibers. (many large mitochnondria, myoglobin and capillaries)
58) Which of the following is not a function of smooth muscle tissue A) Altering the diameter of the respiratory passageway B) Elevating hairs on the arm C) Forcing blood from the heart into the major arteries D) Moving food materials along the digestive tract E) Forcing urine out of the urinary tract
C) Forcing blood from the heart into the major arteries
19) The area in the center of the A band that contains only thick filaments is the A) Z line. B) M line. C) H band. D) I band. E) Zone of overlap.
C) H band.
77) How would blocking the activity of acetylcholinesterase affect skeletal muscle? A) It would make the muscles less excitable. B) It would produce muscle weakness. C) It would cause spastic paralysis (muscles are contracted and unable to relax). D) It would cause flaccid paralysis (muscles are relaxed and unable to contract). E) It would have no effect on skeletal muscles.
C) It would cause spastic paralysis (muscles are contracted and unable to relax).
85) How would an elevated level of thyroid hormone in the body affect skeletal muscles? A) It would stimulate atrophy. B) It would stimulate hypertrophy. C) It would stimulate metabolism. D) It would decrease heat production by muscle tissue. E) It would cause an increase in muscle mass.
C) It would stimulate metabolism.
14) Interactions between actin and myosin filaments of the sarcomere are responsible for A) Muscle fatigue. B) The conduction of neural stimulation to the muscle fiber. C) Muscle contraction. D) Muscle relaxation. E) The striped appearance of skeletal muscle.
C) Muscle contraction.
68) The contraction of a muscle exerts a pull on a bone because A) Muscles are attached to bones by ligaments. B) Muscles are directly attached to bones. C) Muscles are attached to bones by tendons. D) A, B, and C E) none of the above
C) Muscles are attached to bones by tendons. A) Muscles are attached to bones by ligaments. (ligaments bind organs to organs or bones to bones)
9) Skeletal muscle fibers are formed from embryonic cells called A) Sarcomeres. B) Myofibrils. C) Myoblasts. D) Fascicles. E) Myomeres.
C) Myoblasts. Stem cells that fuse to produce each fiber.
26) Each skeletal muscle fiber is controlled by a neuron at a single A) Synaptic knob. B) Sarcomere. C) Neuromuscular junction D) Synaptic cleft. E) Transverse tubule.
C) Neuromuscular junction
35) Which of the following statements is incorrect A) When sarcomeres are fully shortened, contraction cannot occur B) When sarcomeres are slightly less than fully shortened, contraction cannot occur C) Sarcomeres can produce the most tension when stimulated over a relatively wide range of resting lengths D) When the muscle is fully stretched, contraction cannot occur E) All sarcomeres in a muscle fiber contract and relax together
C) Sarcomeres can produce the most tension when stimulated over a relatively wide range of resting lengths (they need an optimum resting zone) B) When sarcomeres are slightly less than fully shortened, contraction cannot occur (it would be slight) D) When the muscle is fully stretched, contraction cannot occur (it would be slight) A) When sarcomeres are fully shortened, contraction cannot occur ( may contract a little) E) All sarcomeres in a muscle fiber contract and relax together
2) Which of the following statements is incorrect? A) The contractions of skeletal muscles pull on tendons and move bones of the skeleton. B) Skeletal muscles are responsible for controlling the openings of the digestive and urinary tracts. C) Skeletal muscles are responsible for the pumping action of the heart. D) Skeletal muscles support the weight of some internal organs. E) Skeletal muscle contractions help maintain body temperature.
C) Skeletal muscles are responsible for the pumping action of the heart.
87) If a person was suffering from severe hyperkalemia, you would expect A) The potassium ion concentration of the interstitial fluid to be less than normal. B) The membrane potential of nerves and muscles to be more negative. C) Skeletal muscles to be unresponsive and the heart muscle would undergo cardiac arrest. D) Muscle weakness and increased strength of twitch contractions. E) both A and D
C) Skeletal muscles to be unresponsive and the heart muscle would undergo cardiac arrest.
71) Which of the following hormones directly stimulates growth of muscle tissue and increased muscle mass? A) Epinephrine. B) Thyroid hormone. C) Testosterone. D) Parathyroid hormone. E) Calcitonin.
C) Testosterone.
29) Action potentials are conducted into a skeletal muscle fiber by A) Motor end plates. B) Neuromuscular junctions. C) Transverse tubules. D) Triads. E) Sarcoplasmic reticulum.
C) Transverse tubules. Action potentials propogated down T tubules causes calcium to release from terminal cisternae A) Motor end plates. =neuromuscular junction B) Neuromuscular junctions. = motor end plate
89) Athletes usually go through a "warm-up" period before engaging in an event. The reason for this "warm-up" period would be to take advantage of A) Incomplete tetanus. B) Complete tetanus. C) Treppe. D) Wave summation. E) Recruitment.
C) Treppe. (increasing tension with repetitive stimulation; staircase effect)
24) At rest, active sites on the actin are blocked by A) Myosin molecules. B) Troponin molecules. C) Tropomyosin molecules. D) Calcium ions. E) ATP molecules.
C) Tropomyosin molecules. In a relaxed muscle fiber each tropomyosin blocks 6-7 active sites on actin preventing myosin from binding with it.
25) At rest, the tropomyosin molecule is held in place by A) Actin molecules. B) Myosin molecules. C) Troponin molecules. D) ATP molecules. E) Calcium ions.
C) Troponin molecules. Loss of a calcium ion from troponin returns tropomyosin to "block mode"
80) In which of the following would the ratio of motor neurons to muscle fibers be the greatest? A) large muscles of the upper arms B) postural muscles of the back C) muscles that control the eye D) leg muscles E) the calf muscle
C) muscles that control the eye (finer motor movement)
66) ATP metabolism normally provides ________ percent of the ATP demands of a resting cell. A) 25 B) 50 C) 70 D) 95 E) 100
D) 95
61) In order for a muscle to contract properly, it requires A) Energy. B) Oxygen. C) Nutrients. D) An adequate blood supply. E) all of the above
E) all of the above
86) How would a drug that competes with acetylcholine for receptors at the motor end plate affect skeletal muscle? A) It would make the muscles more excitable. B) It would produce uncontrolled muscle spasms. C) It would cause spastic paralysis (muscles are contracted and unable to relax). D) It would cause flaccid paralysis (muscles are relaxed and unable to contract). E) It would have no effect on skeletal muscles.
D) It would cause flaccid paralysis (muscles are relaxed and unable to contract).
88) The bacterium that causes tetanus produces a toxin that affects the central nervous system and skeletal muscles, producing powerful tetanic contractions of the skeletal muscles. The toxin probably acts by A) Increasing the amount of acetylcholinesterase in the synapse. B) Making the cells less permeable to sodium ions. C) Increasing the amount of potassium ion in the intercellular fluid. D) Making the cell membranes more permeable to calcium ion. E) Competing with acetylcholine for receptors at the motor end plate.
D) Making the cell membranes more permeable to calcium ion.
54) Each of the following changes in the skeletal muscles is a consequence of aging except that A) Muscle fibers become smaller in diameter B) Muscles become less elastic. C) Muscles fatigue more rapidly. D) Muscle fibers increase their reserves of glycogen E) There is a steady decrease in the number of satellite cells.
D) Muscle fibers increase their reserves of glycogen
3) The dense layer of collagen fibers that surround an entire skeletal muscle is the A) Tendon. B) Epimysium. C) Endomysium. D) Perimysium. E) Fascicle.
D) Perimysium. Bundles muscle fibers into fasicles C) Endomysium. Surrounds each muscle fiber E) Fascicle. A bundle of muscle fiber
59) The ability of smooth muscle to function over a wide range of lengths is called A) Elasticity. B) Contractility. C) Extensibility. D) Plasticity. E) Variability.
D) Plasticity.
76) 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 A) Tetany. B) Treppe. C) Depolarization. D) Rigor mortis. E) Oxygen debt.
D) Rigor mortis.
27) The space between the neuron and the muscle is the A) Synaptic knob. B) Motor end plate. C) Motor unit. D) Synaptic cleft. E) M line.
D) Synaptic cleft.
8) The advantage of having many nuclei in a skeletal muscle fiber is A) The ability to contract. B) The ability to produce more ATP with little oxygen. C) The ability to repair the fiber after an injury. D) The ability to produce large amounts of the enzymes and structural proteins needed for contraction. E) both B and C
D) The ability to produce large amounts of the enzymes and structural proteins needed for contraction.
38) When a muscle is stimulated repeatedly for several seconds with a constant stimulus, the amount of tension gradually increases to a maximum. This phenomenon is called A) Incomplete tetanus. B) Complete tetanus. C) A twitch. D) Wave summation. E) Recruitment.
D) Wave summation. (One wave contraction added to another) B) Complete tetanus. (fused twitches) E) Recruitment. (To respond to stronger stimuli and thus increase the amount of tension, muscles will recruit more motor units until they reach maximal stimulus and all the motor units are recruited) A) Incomplete tetanus. (Force of each twitch builds on the previous one) C) A twitch. (single stimulus/ contraction/relaxation)
40) If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This is called A) Incomplete tetanus. B) Complete tetanus. C) Treppe. D) Wave summation. E) Recruitment.
D) Wave summation. (The arrival of a second stimulus before the relaxation phase has ended result in a second more powerful contraction) A) Incomplete tetanus. (Rapid cycles of contraction and relaxation) B) Complete tetanus. (no relaxation phase) C) Treppe. (A second stimulation immediately after the relaxation phase results in higher maximum tension than the first stimulus)
97) Muscle tone is: A) the feeling of well-being following exercise B) the ability of a muscle to maintain a contraction against an outside force C) the condition of athletes after intensive training D) a state of sustained partial muscular contraction that is vital for the health of muscles E) the result of increased neuromuscular system coordination and increased metabolic rate
D) a state of sustained partial muscular contraction that is vital for the health of muscles
46) During anaerobic glycolysis A) ATP is produced. B) Pyruvic acid is produced. C) Lactic acid is produced if pyruvic acid accumulates. D) all of the above E) A and B only
D) all of the above A) ATP is produced. (results in 4 ATP, uses 2) B) Pyruvic acid is produced. (two molecules of pyruvic acid) C) Lactic acid is produced if pyruvic acid accumulates.
1) Which of the following is not a function of skeletal muscle? A) produce movement B) maintain posture C) maintain body temperature D) all of the above are functions of the skeletal muscle E) A and B only
D) all of the above are functions of the skeletal muscle
90) Muscle tissue that is involuntary: A) cardiac muscle only B) smooth muscle only C) skeletal muscle only D) cardiac muscle and smooth muscle E) cardiac muscle and skeletal muscle
D) cardiac muscle and smooth muscle
56) which of the following is false A) cardiac muscle contraction cannot be summated B) skeletal muscle contraction may be summated C) skeletal muscle control is neural D) cardiac muscle control is neural only
D) cardiac muscle control is neural only A) cardiac muscle contraction cannot be summated (true) B) skeletal muscle contraction may be summated (true) C) skeletal muscle control is neural (true)
79) Each of the following factors would increase the probability of skeletal muscles contracting, except one. Identify the exception. A) increased permeability of the muscle membrane to calcium ions B) increased amounts of acetylcholine in the synaptic cleft C) increased permeability of the muscle membrane to sodium ion D) increased permeability of the muscle membrane to potassium ion E) increased numbers of acetylcholine receptors at the motor end plate
D) increased permeability of the muscle membrane to potassium ion
32) Which of the following acts as an ATPase during the contraction cycle of muscle? A) actin molecules B) troponin molecules C) tropomyosin molecules D) myosin cross-bridges E) the tail portion of the myosin molecule
D) myosin cross-bridges (Myosin ATPase in the head hydrolyzes ATP to ADP and P
96) Creatine phosphate functions in the muscle cell by: A) forming a temporary chemical compound with myosin B) forming a chemical compound with actin C) inducing a conformational change in the myofilaments D) storing energy that will be transferred to ADP to resynthesize ATP as needed E) storing energy that will be transferred to ATP to resynthesize ADP as needed
D) storing energy that will be transferred to ADP to resynthesize ATP as needed
36) Calcium ions are released from the sarcoplasmic reticulum during the ________ of contraction. A) latent period B) contraction phase C) recovery phase D) relaxation phase E) A and B
E) A and B A) latent period ( includes excitation contraction in which Ca is released from SR) B) contraction phase (SR is quickly reabsorbing Calcium ions) C) recovery phase D) relaxation phase (Ca moves from the troponin, and pumped back into the SR)
50) Fast fibers A) Have high resistance to fatigue B) Have a low concentration of myoglobin C) Have many mitochondria D) Produce powerful contraction E) Both B and D
E) Both B and D B) Have a low concentration of myoglobin (less myoglobin, mitochondria and capillaries) D) Produce powerful contraction C) Have many mitochondria (slow fibers have more) A) Have high resistance to fatigue (low fatigue resistance)
73) During muscle contraction, all of the following occur, except A) ATP is hydrolyzed. B) Myosin heads bind to actin. C) The H band becomes shorter. D) Calcium concentration in the sarcomere increases. E) Hemoglobin concentration in muscle fibers increases.
E) Hemoglobin concentration in muscle fibers increases.
18) The area of the sarcomere that contains only thin filaments is the A) Z line. B) M line. C) H band. D) A band. E) I band.
E) I band.
43) The type of contraction in which the muscle fibers produce increased tension but do not shorten is called A) Tetany. B) Treppe. C) Concentric D) Isotonic. E) Isometric
E) Isometric C) Concentric (isotonic: muscle shortens while maintaining tension) D) Isotonic. (isotonic: change in length but not tension)
42) The increase in muscle tension that is produced by increasing the number of active motor units is called A) Incomplete tetanus. B) Complete tetanus. C) Treppe. D) Wave summation. E) Recruitment.
E) Recruitment.
11) The cytoplasm of a skeletal muscle fiber is called the A) Sarcolemma. B) Sarcomere. C) Sarcosome. D) Sarcoplasmic reticulum. E) Sarcoplasm.
E) Sarcoplasm. D) Sarcoplasmic reticulum. Forms a network around each myofibril
92) A motor unit consists of: A) a skeletal muscle and all the neurons that supply it B) a nerve and all of the skeletal muscles supplied by it C) all of the neurons that stimulate a single action D) all of the skeletal muscles that accomplish a single movement E) a neuron and all of the skeletal muscle fibers that it stimulates
E) a neuron and all of the skeletal muscle fibers that it stimulates
93) Acetylcholine is: A) an ion pump B) a source of energy for muscle contraction C) a component of thick myofilaments D) an oxygen binding protein E) a neurotransmjtter
E) a neurotransmitter
53) Which of the following statements are true regarding human muscles? A) All human muscles have both slow and fast fibers. B) Fast fibers are found in the calf muscles. C) Eye and hand muscles are composed of fast fibers. D) Back muscles are mostly composed of endurance fibers. E) both C and D
E) both C and D C) Eye and hand muscles are composed of fast fibers. D) Back muscles are mostly composed of endurance fibers.
91) Which of the following is NOT a function of the muscular system: A) producing movement B) maintaining posture C) stabilizing joints D) generating heat E) hematopoiesis
E) hematopoiesis
95) A muscle twitch differs from a tetanic contraction in that: A) the tetanic contraction is considered abnormal, while the twitch is a normal muscle response B) the tetanic contraction is caused by a single stimulus, while the twitch is caused by very rapid multiple stimuli C) the muscle twitch is prolonged and continuous while a tetanic contraction is brief and jerky D) the muscle twitch occurs only in small muscles while a tetanic contraction occurs in large muscle groups E) the muscle twitch is a brief and jerky movement, while the tetanic contraction is prolonged and continuous
E) the muscle twitch is a brief and jerky movement, while the tetanic contraction is prolonged and continuous (tetanic contraction=complete tetanus)
