Exam Questions Muscular System Histology And Physiology Ch.9 - Seeley’s Anatomy and Physiology 12e Complete Test Bank by Cinnamon VanPutte. DOCX document preview.
Seeley's Anatomy and Physiology, 12e (VanPutte)
Chapter 9 Muscular System: Histology and Physiology
1) Which of the following is NOT a function of skeletal muscle?
A) Body movement
B) Maintenance of posture
C) Respiration
D) Constriction of organs
E) Production of heat
2) Which of the following actions is caused by contraction of skeletal muscle?
A) Contraction of the heart
B) Moving your feet in walking
C) Movement of food through the digestive tract
D) Emptying of the urinary bladder
E) Vasoconstriction
3) Smooth muscle and cardiac muscle are similar in that they both
A) are under involuntary control.
B) are striated.
C) are widely distributed in the body.
D) have multiple nuclei.
E) are under voluntary control.
4) The capacity of a muscle cell to shorten forcefully is known as
A) contractility.
B) excitability.
C) extensibility.
D) elasticity.
E) flexibility.
5) Muscles exhibit the property of excitability. This means that the muscle
A) shortens its length.
B) recoils to its original resting length.
C) stretches beyond its normal length.
D) responds to stimulation by the nervous system.
E) excites itself.
6) Identify the statement concerning general functional characteristics of muscle that is true.
A) Muscle tissue shortens forcefully but lengthens passively.
B) Muscle tissue shortens passively but lengthens forcefully.
C) Muscle tissue can get shorter, but cannot get longer.
D) Muscle tissue can get longer, but cannot get shorter.
E) None of these statements are true.
7) Identify the statement concerning skeletal muscle that is true.
A) It comprises about 20% of the body's weight.
B) It propels urine through the urinary tract.
C) Its function is largely under involuntary control.
D) It is a kind of connective tissue.
E) It is responsible for locomotion.
8) Which of the following statements about muscle tissue is true?
A) Skeletal muscle is capable of spontaneous contraction.
B) Smooth muscle is found in the walls of hollow organs.
C) Cardiac muscle cells have multiple nuclei.
D) Smooth muscle cells are long and cylindrical.
E) There is a small amount of smooth muscle in the heart.
9) Skeletal muscle fibers
A) possess striations.
B) can contract but are not extensible or excitable.
C) do not require nerve innervation to contract.
D) increase dramatically in number after birth.
E) are found in the walls of the stomach.
10) Which type of muscle tissue has spindle-shaped cells?
A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
D) Both skeletal and cardiac muscle are correct.
E) Both cardiac and smooth muscle are correct.
11) Which type of muscle tissue possesses striations?
A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
D) Both skeletal and cardiac muscle are correct.
E) Both cardiac and smooth muscle are correct.
12) Which type of muscle tissue is autorhythmic?
A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
D) Both skeletal and cardiac muscle are correct.
E) Both cardiac and smooth muscle are correct.
13) Which type of muscle tissue is multinucleated?
A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
D) Both skeletal and cardiac muscle are correct.
E) Both cardiac and smooth muscle are correct.
14) Which type of muscle tissue has cells that branch?
A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
D) Both skeletal and cardiac muscle are correct.
E) Both cardiac and smooth muscle are correct.
15) Which type of muscle tissue would cause flexion and extension of the arm?
A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
16) Which type of muscle tissue causes contraction of the heart?
A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
17) Which type of muscle tissue causes vasoconstriction?
A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
18) Which type of muscle tissue causes peristalsis?
A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
19) Which type of muscle tissue has neuromuscular junctions?
A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
20) Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the
A) number of muscle fibers.
B) size of muscle fibers.
C) number of striations.
D) number of nuclei within the muscle fibers.
E) number of muscle cells.
21) Skeletal muscle develops from cells called
A) fascicles.
B) myoblasts.
C) myofibrils.
D) myotomes.
E) fasciculi.
22) A fascicle
A) is a bundle of reticular fibers.
B) is surrounded by perimysium.
C) is only found in smooth muscle.
D) possesses an external lamina.
E) is a bundle of collagen fibers.
23) Epimysium
A) surrounds individual muscles.
B) separates muscle fibers.
C) connects muscles to bone.
D) is a type of muscle tissue.
E) is a type of nerve tissue.
24) Endomysium is a delicate network of loose connective tissue that
A) surrounds each muscle fiber.
B) forms a sheath around a fascicle.
C) is composed of elastic fibers.
D) separates individual muscles.
E) penetrates muscle fibers.
25) Which of the following connective tissue layers is outside all the others?
A) Perimysium
B) Endomysium
C) Epimysium
D) Paramysium
E) Sarcolemma
26) Which of the following is true about skeletal muscle?
A) Sensory neurons stimulate muscles to contract.
B) There are very few blood vessels in skeletal muscle.
C) Every muscle fiber receives a branch of an axon from the nerve.
D) There are very few nerve fibers in a muscle.
E) All of the choices are true.
27) List the following structures in order from smallest to largest.
(1) Muscle fiber
(2) Myofilament
(3) Myofibril
(4) Muscle fascicle
A) 4, 2, 3, 1
B) 2, 1, 4, 3
C) 3, 1, 4, 2
D) 2, 3, 1, 4
E) 1, 2, 3, 4
28) Muscle myofibrils
A) are found in the sarcolemma.
B) extend from the sarcolemma to the T-tubule.
C) contain myosin and actin myofilaments.
D) hold muscle fibers together.
E) do not appear striated.
29) Myosin is also known as the
A) thick myofilament.
B) thin myofilament.
C) intermediate myofilament.
D) short myofilament.
E) sarcomere.
30) Actin myofilaments
A) resemble bundles of minute golf clubs.
B) contain both myosin and tropomyosin.
C) are held in place by the M line.
D) contain strands of fibrous actin.
E) are the thickest proteins in muscle.
31) Which of the following is part of a thin myofilament?
A) ATP-binding site
B) Globular (G) actin
C) Calcium
D) Myosin
E) Sarcolemma
32) Troponin
A) has two subunits.
B) is part of the myosin myofilament.
C) is a long, flexible protein.
D) has a calcium-binding site.
E) binds to ATP.
33) Which of the following is composed of myosin molecules?
A) Thick myofilaments
B) I bands
C) Z disks
D) Sarcolemma
E) Tropomyosin
34) The active sites to which cross-bridges attach are found on the
A) sarcoplasmic reticulum.
B) actin myofilaments.
C) Z disks.
D) T tubules.
E) myosin myofilaments.
35) ATPase is found in
A) F-actin strands.
B) G-actin globular units.
C) myosin heads.
D) tropomyosin grooves.
E) troponin molecules.
36) Which of the following is NOT a property of the myosin head?
A) They form cross-bridges with the active sites of actin.
B) They have a hinge region to bend and straighten.
C) They bind to troponin.
D) They have ATPase activity.
E) They bind to ATP.
37) The region of the sarcomere that contains both actin and myosin myofilaments is called the
A) I band.
B) A band.
C) Z disk.
D) H zone.
E) M line.
38) A sarcomere extends from
A) one Z disk to an adjacent Z disk.
B) one T tubule to the next T tubule.
C) the middle of the I band to the middle of the A band.
D) the H zone to the I band.
E) the M line to the next M line.
39) Which of the following is mismatched?
A) I band – contains only actin
B) M line – middle of the H zone
C) Z disk – structure between adjacent sarcomeres
D) Myosin myofilaments – thin myofilaments
E) Actin myofilaments – thin myofilaments
40) A sarcomere is the
A) plasma membrane of a muscle fiber.
B) cytoplasm of a muscle fiber.
C) structural and functional unit of the skeletal muscle fiber.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin or myosin.
41) Sarcoplasm is the
A) plasma membrane of a muscle fiber.
B) cytoplasm of a muscle fiber.
C) structural and functional unit of the skeletal muscle fiber.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin or myosin.
42) A myofilament is the
A) plasma membrane of a muscle fiber.
B) cytoplasm of a muscle fiber.
C) structural and functional unit of the skeletal muscle fiber.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin or myosin.
43) The sarcolemma is the
A) plasma membrane of a muscle fiber.
B) cytoplasm of a muscle fiber.
C) structural and functional unit of the skeletal muscle fiber.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin.
44) A myofibril is the
A) plasma membrane of a muscle fiber.
B) cytoplasm of a muscle fiber.
C) structural and functional unit of the skeletal muscle fiber.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin.
45) Which of the following statements regarding the sliding filament model is false?
A) Actin and myosin do not shorten during contraction.
B) Both actin and myosin myofilaments shorten during contraction.
C) The sarcomere shortens.
D) The I band and H zones become narrower during contraction.
E) The A band remains constant in length.
46) The length of the resting sarcomere is
A) longer than the length of a contracted sarcomere.
B) shorter than the length of a contracted sarcomere.
C) the same length as a contracted sarcomere.
D) the same length as the muscle fiber.
E) the same length as the myofibril.
47) The model that describes the contraction of the muscle is called the
A) contraction cycle.
B) power stroke.
C) sliding filament model.
D) slipping fibril mechanism.
E) paddle model.
48) The electrical properties of cells are the result of
A) ion concentration differences across the plasma membrane.
B) receptor sites that are present on the plasma membrane.
C) phosphorylation reactions within the cytoplasm.
D) phospholipids in the plasma membrane.
E) None of these choices are correct.
49) Which of the following causes an unequal ion concentration across the resting plasma membrane?
A) The functioning of the sodium-chloride pump
B) Negatively charged proteins not readily diffusing across the plasma membrane
C) The attraction of chloride ions to other intracellular anions
D) The repulsion of potassium ions by the intracellular anions
E) The attraction of sodium ions to chloride ions
50) Which of the following is true during the resting membrane potential?
A) Sodium ion concentration is greater inside cells.
B) Negatively charged proteins are more concentrated outside the cell.
C) A greater concentration of calcium ions is found inside the cell.
D) Potassium is concentrated primarily inside the cell.
E) None of these choices reflect what occurs during the resting membrane potential.
51) The outside of the resting plasma membrane is ________ relative to the inside of the resting plasma membrane.
A) positively charged
B) negatively charged
C) electrically neutral
D) recharged
E) None of these choices are correct.
52) The plasma membrane of an excitable cell is more permeable to K+ because
A) of its positive electrical charge.
B) there are more leak ion channels for K+ than Na+.
C) protein molecules cannot exit through the plasma membrane.
D) calcium ions block Na+ and Cl- channels.
E) there are more gated channels for K+.
53) In which of the following situations does a resting membrane potential exist?
A) A relaxed muscle fiber
B) A conducting neuron
C) A stimulated sensory receptor in the skin
D) A contracting cardiac muscle cell
E) The eye seeing an image
54) Channels that open or close in response to changes in the electrical charge or voltage across the plasma membrane are called
A) ligand-gated ion channels.
B) leak ion channels.
C) relegated ion channels.
D) voltage-gated ion channels.
E) obligated ion channels.
55) Which of the following changes have the potential to dramatically affect the potential difference across the plasma membrane?
A) Increased permeability of the membrane to Na+
B) Increased intracellular concentration of K+
C) Any change in the rate at which the sodium-potassium pump works
D) Increased permeability of the membrane to Na+ and increased intracellular concentration of K+
E) Increased permeability of the membrane to Na+, increased intracellular concentration of K+, and any change in the rate at which the sodium-potassium pump works
56) Which of the following situations occurs in electrically excitable cells?
A) When Na+ ion channels open, K+ ion channels close.
B) The sodium-potassium pump moves sodium into the cell.
C) Depolarization causes voltage-gated sodium ion channels to open.
D) Sodium ion channels are opened by high extracellular calcium levels.
E) The opening and closing of ligand-gated channels cause depolarization.
57) Depolarization of the plasma membrane occurs when there is a rapid influx (inflow) of
A) potassium ions.
B) chloride ions.
C) calcium ions.
D) sodium ions.
E) amino acids.
58) An action potential
A) occurs when the local potential reaches threshold level.
B) is not propagated.
C) has no repolarization phase.
D) is an example of negative feedback.
E) can be of varying strengths depending on strength of the stimulus.
59) A stimulus either causes an action potential or it doesn't. This is called
A) an all-or-none response.
B) a graded response.
C) a latent period response.
D) a relative refractory response.
E) an arbitrary response.
60) When repolarization of the plasma membrane is complete, the
A) cell dies.
B) cell regenerates.
C) cell no longer has a potential difference across its membrane.
D) cell is no longer responsive.
E) original polarity of the cell is restored.
61) A muscle fiber will respond to a stimulus when that stimulus reaches the ________ level.
A) threshold
B) relaxation
C) rigor mortis
D) recruitment
E) resting
62) 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) neuromuscular junctions.
B) sarcomeres.
C) myofilaments.
D) Z disks.
E) cell bodies of neurons.
63) Synaptic vesicles in the neuromuscular junction contain
A) calcium.
B) ATP.
C) acetylcholine.
D) acetylcholinesterase.
E) sodium.
64) Which of the following structures contains the other four items listed?
A) Postsynaptic membrane
B) Presynaptic terminal
C) Synaptic cleft
D) Neuromuscular junction
E) Receptors on postsynaptic membrane
65) Acetylcholine binds to a membrane bound receptor and causes ligand-gated sodium channels to open and results in
A) hyperpolarization.
B) depolarization.
C) hypoplarization.
D) no change in membrane potential.
E) There is not enough information to predict the outcome.
66) When an action potential reaches the presynaptic terminal,
A) calcium ions diffuse into the presynaptic terminal through voltage-gated ion channels.
B) acetylcholine moves into the presynaptic terminal.
C) a local potential is generated in the presynaptic terminal.
D) ligand-gated ion channels in the presynaptic terminal are opened.
E) nothing else happens.
67) Lack of acetylcholinesterase in the synaptic cleft would result in
A) a decrease in acetylcholine production by the motor neuron.
B) continuous stimulation of the postsynaptic membrane.
C) rapid degradation of acetylcholine.
D) relaxation of the muscle.
E) continuous stimulation of the presynaptic membrane.
68) Acetylcholine is released from the presynaptic terminal by the process of
A) exocytosis.
B) diffusion.
C) phagocytosis.
D) active transport.
E) endocytosis.
69) Too much acetylcholinesterase causes
A) continuous stimulation of the muscle fiber.
B) rapid degradation of acetylcholine.
C) voltage-gated Ca2+ channels opening in the presynaptic terminal.
D) an increase in Na+ uptake by the muscle fiber.
E) exocytosis of synaptic vesicles.
70) Which of the following events occurs on the postsynaptic membrane?
A) Acetylcholine production
B) Rapid degradation of acetylcholine
C) Release of neurotransmitter
D) Neurotransmitter combines with a receptor molecule
E) Release of Ca2+
71) If Na+ cannot enter a muscle fiber in response to a stimulus,
A) contraction cannot occur.
B) relaxation cannot occur.
C) Na+ will be released from the sarcoplasmic reticulum instead.
D) the active sites are left exposed.
E) the action potential travels into the muscle anyway.
72) T tubules are invaginations of the
A) sarcoplasmic reticulum.
B) sarcomere.
C) myofibril.
D) sarcoplasm.
E) sarcolemma.
73) T tubules
A) provide nutrients to the muscle fiber.
B) generate new muscle fibers.
C) conduct action potentials deep into the muscle fiber.
D) release acetylcholine.
E) store calcium ions.
74) The sarcoplasmic reticulum
A) stores Ca2+.
B) shortens during muscle contraction.
C) transmits nerve impulses to the myofibrils.
D) connects adjacent sarcomeres.
E) covers the muscle fiber.
75) Arrange these structures as they participate in excitation-contraction.
A) T tubules, sarcolemma, Ca2+, sarcoplasmic reticulum
B) Ca2+, T tubules, sarcolemma, sarcoplasmic reticulum
C) Sarcolemma, T tubules, sarcoplasmic reticulum, Ca2+
D) Sarcoplasmic reticulum, Ca2+, T tubules, sarcolemma
E) Sarcolemma, sarcoplasmic reticulum, Ca2+, T tubules
76) 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, 5, 2, 3, 4
B) 1, 3, 4, 2, 5
C) 1, 2, 3, 4, 5
D) 1, 3, 2, 5, 4
E) 1, 4, 3, 2, 5
77) In excitation-contraction coupling,
A) Ca2+ must bind with myosin to expose active sites on actin.
B) myosin heads bind to exposed active sites on actin.
C) cross-bridges form between myosin heads and Ca2+.
D) movement of the troponin-tropomyosin complex causes actin myofilaments to slide.
E) ATP binds to actin myofilaments.
78) When the myosin head flexes into a bend, pulling the actin filament along with it, this is called the
A) action reaction.
B) power stroke.
C) recovery stroke.
D) muscle tone.
E) action potential.
79) One ATP molecule is required for
A) formation of the cross-bridge.
B) movement of the cross-bridge.
C) release of the cross-bridge.
D) formation of the cross-bridge and for movement of the cross-bridge.
E) formation of the cross-bridge, for movement of the cross-bridge, and for release of the cross-bridge.
80) In order for muscle relaxation to occur,
A) Ca2+ must be transported to troponin.
B) power strokes slow down.
C) the active sites on actin must be blocked.
D) Na+ must be actively transported to troponin.
E) the active sites on myosin must be uncovered.
81) A drug that interferes with the active transport of Ca2+ from the sarcoplasm back into the sarcoplasmic reticulum would result in
A) relaxation of the muscle fiber.
B) contraction with no relaxation.
C) muscle hypertrophy.
D) fibrosis of the muscle.
E) an imbalance of blood calcium.
82) After contraction has occurred, the Ca2+ are
A) destroyed by cholinesterase.
B) chemically bound to the cross bridges.
C) secreted by the Golgi apparatus to the outside of the cell.
D) released from troponin.
E) returned to the sarcolemma.
83) During the contraction phase of a muscle twitch,
A) acetylcholine stimulates the pre-synaptic terminal.
B) Na+ diffuse into the muscle fiber.
C) actin-myosin cross-bridges form.
D) Ca2+ are transported back to the sarcoplasmic reticulum.
E) the action potential travels down the T tubule.
84) Which of the following events occurs during the lag phase of a muscle twitch?
A) Muscle fibers shorten.
B) Cross-bridges form, move, release, and reform many times.
C) The action potential is propagated from presynaptic to postsynaptic membrane.
D) Ca2+ are pumped back into the sarcoplasmic reticulum.
E) All of these events occur in the lag phase.
85) The time between application of the stimulus to a motor neuron and the beginning of contraction is called the ________ phase.
A) contraction
B) relaxation
C) latent or lag
D) refractory
E) threshold
86) Which of the following would occur as a result of a single muscle contraction?
A) Tetanus
B) Tone
C) Treppe
D) Twitch
E) Paralysis
87) Which of the following will respond to a threshold stimulus with an all-or-none contraction?
A) A single muscle fiber
B) A single motor unit
C) A whole muscle
D) Both a single muscle fiber and a single motor unit are correct.
E) A single muscle fiber, a single motor unit, and a whole muscle are all correct.
88) Which of the following is true?
A) Muscle fatigue has no influence on the force of contractions.
B) A threshold stimulus will cause contraction of a muscle fiber.
C) A subthreshold stimulus causes a muscle contraction.
D) Motor units do not obey the "all or none" law.
E) A threshold stimulus will not affect motor units.
89) Whole muscles can respond in a graded fashion to stimuli by varying
A) the force of contraction of individual muscle fibers.
B) the number of motor units recruited.
C) the amplitude of the action potential.
D) the frequency of stimulus.
E) thresholds.
90) A sustained muscle contraction is known as ________.
A) tetanus
B) tone
C) treppe
D) twitch
E) paralysis
91) Tetanus of a muscle is thought to be caused by
A) high Ca2+ concentrations in the sarcoplasm.
B) the rapid movement of Na+ back into the sarcoplasmic reticulum.
C) an increase in stimulus strength.
D) increased temperature in the active muscle.
E) decreased amounts of Ca2+ in muscle tissue.
92) Which of the following helps explain the increased tension seen in multiple wave summation?
A) Increased motor unit recruitment
B) Increased concentration of Ca2+ around the myofibrils
C) Exposure of more active sites on myosin myofilaments
D) The breakdown of elastic elements in the cell
E) Decreased stimulus frequency
93) A condition in which stimuli occur so rapidly that there are no intervening relaxations between contractions is called
A) complete tetanus.
B) incomplete tetanus.
C) involuntary paralysis.
D) all or none tetanus.
E) treppe.
94) Treppe
A) can contribute to improved muscle efficiency.
B) may be due to an increase in the level of Ca2+ around the myofibril.
C) is an example of a graded response.
D) is achieved during warm-up exercises.
E) All of these choices are correct.
95) The stretch of elastic components of a muscle adds to the increased tension during
A) incomplete tetanus.
B) twitch.
C) multiple wave summation.
D) all-or-none response.
E) None of the choices are correct.
96) Incomplete tetanus
A) is the time during which the tissue cannot respond again.
B) results in complete and incomplete tetanus.
C) is the condition in which the muscle fiber only partially relaxes between contractions.
D) is the condition in which stimuli occur so rapidly that there are no intervening relaxations.
E) is the constant tension produced by muscles for long periods of time.
97) Muscle tone
A) is a time during which the tissue cannot respond again.
B) results in complete and incomplete tetanus.
C) is a condition in which the muscle fiber only partially relaxes between contractions.
D) is a condition in which stimuli occur so rapidly that there are no intervening relaxations.
E) is a constant tension produced by muscles for long periods of time.
98) The refractory period
A) is the time during which the tissue cannot respond again.
B) results in complete and incomplete tetanus.
C) is the condition in which the muscle fiber only partially relaxes between contractions.
D) is the condition in which stimuli occur so rapidly that there are no intervening relaxations.
E) is the constant tension produced by muscles for long periods of time.
99) Multiple wave summation
A) is a time during which the tissue cannot respond again.
B) results in complete and incomplete tetanus.
C) is a condition in which the muscle fiber only partially relaxes between contractions.
D) is a condition in which stimuli occur so rapidly that there are no intervening relaxations.
E) is a constant tension produced by muscles for long periods of time.
100) Complete tetanus
A) is the time during which the tissue cannot respond again.
B) results in complete and incomplete tetanus.
C) is the condition in which the muscle fiber only partially relaxes between contractions.
D) is the condition in which stimuli occur so rapidly that there are no intervening relaxations.
E) is the constant tension produced by muscles for long periods of time.
101) A proper definition of muscle tone is
A) constant tension produced by muscles for long periods of time.
B) a feeling of well-being following exercise.
C) the ability of a muscle to maintain a contraction against an outside force.
D) muscles contracting together.
E) warm-up of muscle tissue.
102) Movements of the body are usually smooth and occur at differing rates because
A) they are a mixture of isotonic and isometric contractions.
B) motor units contract out of phase at their own particular rates.
C) most muscle contractions closely resemble individual muscle twitches.
D) muscles of different sizes contract at different rates.
E) of the all-or-none principle.
103) Which of the following statements concerning types of muscle contractions is false?
A) In isometric contractions, the amount of tension produced by the muscle is constant.
B) In isotonic contractions, the muscle fibers shorten.
C) The contractile processes in isometric and isotonic contractions are the same.
D) Most skeletal muscle contractions are a combination of isometric and isotonic contractions.
E) In isotonic contractions, the amount of tension produced by the muscle fibers is constant during the contraction.
104) Concentric contractions occur when
A) the muscle produces increasing tension as it shortens.
B) the tension and length of the muscle remain constant during a contraction.
C) tension in a muscle is maintained while the muscle increases in length.
D) the muscle produces tension while the length of the muscle increases.
E) isometric contractions occur.
105) An isotonic contraction is described as
A) action potential frequency is high enough that no relaxation of muscle fibers occurs.
B) a muscle produces constant tension during contraction.
C) a muscle produces an increasing tension during contraction.
D) a muscle produces increasing tension as it shortens.
E) a muscle produces tension, but the length of the muscle is increasing.
106) Tetanus of muscles is described as
A) action potential frequency is high enough that no relaxation of muscle fibers occurs.
B) a muscle produces constant tension during contraction.
C) a muscle produces an increasing tension during contraction.
D) a muscle produces increasing tension as it shortens.
E) a muscle produces tension, but the length of the muscle is increasing.
107) An eccentric contraction is described as
A) action potential frequency is high enough that no relaxation of muscle fibers occurs.
B) a muscle produces constant tension during contraction.
C) a muscle produces an increasing tension during contraction.
D) a muscle produces increasing tension as it shortens.
E) a muscle produces tension, but the length of the muscle is increasing.
108) An isometric contraction is described as
A) action potential frequency is high enough that no relaxation of muscle fibers occurs.
B) a muscle produces constant tension during contraction.
C) a muscle produces an increasing tension as the length remains constant.
D) a muscle produces increasing tension as it shortens.
E) a muscle produces tension, but the length of the muscle is increasing.
109) A concentric contraction is described as
A) action potential frequency is high enough that no relaxation of muscle fibers occurs.
B) a muscle produces constant tension during contraction.
C) a muscle produces an increasing tension during contraction.
D) a muscle produces increasing tension as it shortens.
E) a muscle produces tension, but the length of the muscle is increasing.
110) Which of the following is true?
A) The greater the overlap of actin and myosin, the stronger the contraction.
B) Overstretching a muscle will increase its tension.
C) Optimal actin and myosin overlap will produce maximal contraction.
D) The greatest amount of tension is achieved when actin and myosin do not overlap.
E) Tension is great when actin and myosin overlap as much as they can.
111) Which of the following conditions in muscle fibers would contribute to muscle fatigue?
A) The emotional state of an individual
B) Depletion of ATP reserves
C) Inability of the motor neuron to produce sufficient quantities of acetylcholine
D) Depletion of neurotransmitter
E) Blocked receptors in the postsynaptic membrane
112) The type of muscle fatigue known as "psychological fatigue" is the result of
A) depleted ATP reserves.
B) increased Ca2+ concentration in the sarcoplasm.
C) decreased levels of acetylcholine.
D) the emotional state of an individual.
E) None of these choices are correct.
113) Physiological contracture
A) occurs when muscles are resting.
B) is a condition in which cross-bridges cannot release.
C) is caused by an abundance of ATP in muscle fibers.
D) results when muscles are well exercised.
E) results when the neurotransmitter remains in the receptor.
114) Rigor mortis occurs after death because
A) cross-bridges form but can't release.
B) Ca2+ is actively transported back to the sarcoplasmic reticulum.
C) anaerobic respiration is occurring.
D) myosin levels decline at death.
E) cross-bridges never form.
115) During resting conditions, ________ is synthesized to store energy.
A) Ca2+
B) creatine phosphate
C) creatinine
D) lactate
E) pyruvate
116) You are hired to work in a laboratory to measure the rate of human muscle contraction. Which of the following might decrease in quantity in muscle fibers undergoing contractions?
A) ATP
B) Carbon dioxide
C) Water
D) Lactate
E) Na+
117) A by-product of anaerobic respiration in muscle fibers is
A) uric acid.
B) hydrochloric acid.
C) lactate.
D) oxygen.
E) pyruvate.
118) Alex is participating in a 50-meter dash. Predict the most important chemical process his muscles will rely on during this race.
A) Aerobic respiration
B) Anaerobic respiration
C) Creatine phosphate breakdown
D) Nuclear reactions
E) Both anaerobic respiration and creatine phosphate breakdown are correct.
119) Aerobic respiration
A) produces ATP molecules faster than anaerobic respiration.
B) yields as many as 36 ATP per glucose molecule metabolized.
C) occurs whether oxygen is present or not.
D) occurs entirely in the cytoplasm.
E) occurs in the ribosomes.
120) A lack of glycolytic enzymes within skeletal muscle fibers would impair which type of ATP-yielding process?
A) Anaerobic respiration
B) Aerobic respiration
C) Both anaerobic respiration and aerobic respiration are correct.
121) A lack of mitochondria within skeletal muscle fibers would impair which ATP-yielding chemical process?
A) Anaerobic respiration
B) Aerobic respiration
C) Both anaerobic respiration and aerobic respiration are correct.
122) Heather is watching a movie. Which type of chemical pathway does her muscles depend on at this time?
A) Anaerobic respiration
B) Aerobic respiration
C) Both anaerobic respiration and aerobic respiration are correct.
123) Randy is participating in a strong man competition and is required to pull a yacht as far as he can. Which type of chemical process will his skeletal muscles rely on during this competition?
A) Anaerobic respiration
B) Aerobic respiration
C) Both anaerobic respiration and aerobic respiration are correct.
124) Which type of respiration rapidly produces ATP for short time periods?
A) Anaerobic respiration
B) Aerobic respiration
C) Both anaerobic respiration and aerobic respiration are correct.
125) When skeletal muscle is producing CO2 and water while making ATP, which chemical processes could be active at this time?
A) Anaerobic respiration
B) Aerobic respiration
C) Both anaerobic respiration and aerobic respiration are correct.
126) Oxygen deficit represents
A) the amount anaerobic metabolism must increase after exercise.
B) the amount of O2 converted to lactate during exercise.
C) the amount of CO2 that cells need to eliminate.
D) conversion of pyruvate to lactate.
E) the amount of O2 that cells need to replenish ATP supplies after exercise.
127) The elevated oxygen consumption relative to activity level after exercise has ended is called
A) oxygen deficit.
B) oxygen debt.
C) oxygen repayment.
D) excess post-exercise oxygen consumption.
E) anaerobic recovery.
128) Callie is a world class marathon runner. Which of the descriptions about her dominant type of skeletal muscle is FALSE?
A) They split ATP slowly.
B) They have large deposits of myoglobin.
C) They are well adapted to anaerobic activity.
D) They have a well-developed blood supply.
E) They have low glycogen stores.
129) What is a cross-bridge?
A) A protein found along the groove of the F-actin double helix
B) A T tubule and two adjacent terminal cisternae
C) The combination of myosin heads with active sites on actin molecules
D) The movement of myosin head while attached to actin myofilament
E) After exercise, the O2 taken in that exceeds the O2 required for resting metabolism
130) What is the power stroke?
A) A protein found along the groove of the F-actin double helix
B) A T tubule and two adjacent terminal cisternae
C) The combination of myosin heads with active sites on actin molecules
D) The movement of myosin head while attached to actin myofilament
E) After exercise, the O2 taken in that exceeds the O2 required for resting metabolism
131) What is tropomyosin?
A) A protein found along the groove of the F-actin double helix
B) A T tubule and two adjacent terminal cisternae
C) The combination of myosin heads with active sites on actin molecules
D) The movement of myosin head while attached to actin myofilament
E) After exercise, the O2 taken in that exceeds the O2 required for resting metabolism
132) What is a triad?
A) A protein found along the groove of the F-actin double helix
B) A T tubule and two adjacent terminal cisternae
C) The combination of myosin heads with active sites on actin molecules
D) The movement of myosin head while attached to actin myofilament
E) After exercise, the O2 taken in that exceeds the O2 required for resting metabolism
133) What is an oxygen deficit?
A) A protein found along the groove of the F-actin double helix
B) A T tubule and two adjacent terminal cisternae
C) The combination of myosin heads with active sites on actin molecules
D) The movement of myosin head while attached to actin myofilament
E) After exercise, the O2 taken in that exceeds the O2 required for resting metabolism
134) Which of the following correctly describes myoglobin's special function in muscle tissue?
A) Breaks down glycogen
B) Synthesizes ATP
C) Acts as a reservoir for O2
D) Produces action potentials
E) Stores glucose
135) Consider the following four phrases and select the one that does not belong with the others.
A) Anaerobic metabolism
B) Lactate production
C) Fast twitch fibers
D) Fuels runner in a marathon
E) Muscle fibers split ATP rapidly
136) Which of the following statements concerning fast-twitch muscle fibers is true?
A) They split ATP rapidly.
B) They have large deposits of myoglobin.
C) They are well adapted to aerobic metabolism.
D) They have a well-developed blood supply.
E) They have many mitochondria.
137) Intense exercise that results in a great deal of anaerobic activity
A) converts some slow-twitch fibers into fast-twitch fibers.
B) increases muscular strength and mass.
C) enlarges slow-twitch fibers.
D) decreases the efficiency of fast-twitch fibers.
E) decreases muscle strength and mass.
138) Aerobic exercise
A) increases vascularity of muscle.
B) develops fatigue-resistant fast-twitch fibers.
C) can increase the efficiency of slow-twitch fibers.
D) can increase the number of mitochondria in muscle fibers.
E) All of these choices are correct.
139) Muscle hypertrophy results from increased numbers of
A) myofibrils and sarcomeres.
B) muscle fibers.
C) motor units.
D) muscles.
E) muscle cells.
140) Increased strength of a trained muscle is due to
A) an increased number of muscle fibers.
B) the nervous system's ability to recruit a large number of motor units simultaneously.
C) elimination of unnecessary enzymes and metabolic pathways.
D) elimination of all adipose tissue.
E) elimination of unnecessary connective tissue.
141) Betsy took a fall and broke her arm, which required that she wear a cast for a prolonged period of time. When she took the cast off, she was alarmed to see that her muscles
A) looked the same as they did before the fall.
B) had undergone atrophy.
C) had undergone hypertrophy.
D) seemed to have an increase in blood flow.
142) Select the phrase that does not belong with the others.
A) Muscle atrophy
B) Immobilization
C) Decrease in number of myofibrils
D) Loss of nerve stimulation
E) Increased vascularity
143) Susan slipped on the ice and was unable to be fully mobile for several days. What disruption to homeostasis would you predict she experienced during her immobile period in terms of her muscular system?
A) Susan's metabolic rate was raised, and it initiated sweating.
B) Susan was more cold than usual because her inactivity prevented her muscles from helping to regulate her body temperature.
C) Susan's uninjured muscles overcompensate for the inactive ones by contracting spontaneously.
144) Maureen is hiking in the cold, and to maintain homeostasis her body begins to
A) increase heat loss from the skin.
B) release chemicals to initiate a high fever.
C) shiver.
D) reduce her blood pressure.
E) vasodilate vessels in her head and neck.
145) When comparing smooth and skeletal muscle cells, which of the following statements is true?
A) Smooth muscle cells have striations.
B) The myofilaments in smooth muscle do not form sarcomeres.
C) Smooth muscle cells are larger than skeletal muscle cells.
D) Smooth muscle has a lot of actin and myosin.
E) Smooth muscle cells are multinucleated.
146) Which of the following statements concerning smooth muscle is true?
A) It contains many sarcomeres.
B) Caveolae seem to take the place of the myofibrils.
C) A calcium-calmodulin complex initiates cross-bridge formation.
D) The cells are large and multinuclear.
E) It has a well-developed sarcoplasmic reticulum.
147) In smooth muscle, most of the Ca2+ needed for muscle contraction
A) is in the dense bodies.
B) enters from extracellular fluid.
C) is attached to the intermediate filaments.
D) must be activated by myosin kinase.
E) is stored in the sarcoplasmic reticulum.
148) In smooth muscle, cross-bridging occurs due to
A) Ca2+ binding to troponin.
B) Ca2+ binding to calmodulin.
C) myosin kinase adding a phosphate to myosin heads.
D) both Ca2+ binding to troponin and calmodulin.
E) both Ca2+ binding to calmodulin and myosin kinase adding a phosphate to myosin heads.
149) Which of the following is NOT true of the latch state of smooth muscle contraction?
A) Myosin phosphatase removes the phosphate group from myosin.
B) It explains why smooth muscle can sustain tension for long periods of time.
C) It occurs when the phosphate is removed while the cross-bridges are attached to actin.
D) It occurs when the phosphate is removed while the cross-bridges are not attached to actin.
E) It allows contraction without a large energy expenditure.
150) Myosin phosphatase
A) activates myosin kinase.
B) forms the cross-bridge.
C) removes phosphate from myosin.
D) binds to calcium-calmodulin complex.
E) opens Ca2+-channels.
151) Visceral smooth muscle
A) may contain groups of cells that function as an independent unit.
B) occurs in sheets and exhibits numerous gap junctions.
C) contracts only when stimulated.
D) does not function as a unit.
E) All of these choices are correct.
152) Multiunit smooth muscle is located in the
A) gastrocnemius.
B) wall of the GI tract.
C) wall of blood vessels.
D) wall of the heart.
E) reproductive system.
153) Smooth muscle
A) responds in an all-or-none fashion.
B) depolarizes when both Na+ and Ca2+ diffuse into the cell.
C) has fast waves of depolarization.
D) has fast waves of repolarization.
E) has a resting membrane potential that is more negative than skeletal muscle fibers.
154) Functionally, smooth muscle
A) is well adapted to anaerobic metabolism.
B) exhibits autorhythmic contractions.
C) contracts in response to slow increases in length.
D) is unable to maintain tone.
E) rapidly develops an oxygen deficit.
155) In a laboratory experiment, the resting membrane potential of a muscle is measured and is found to be more negative. Which of the following has occurred?
A) Hyperpolarization
B) Repolarization
C) Depolarization
D) Isopolarization
E) Hypopolarization
156) Smooth muscle is regulated by all of the following except
A) the autonomic nervous system.
B) neurotransmitters.
C) the somatic nervous system.
D) hormones.
E) prostaglandins.
157) The type of neurotransmitter or hormone that binds to receptors on smooth muscle plasma membranes determines the response of the muscle.
158) The diffusion of Ca2+ into a smooth muscle cell does not depolarize the membrane so no action potential occurs.
159) An antibody test on smooth muscle reveals fewer dense bodies and intermediate filaments in a patient with a colon disorder. What is the purpose of these structures?
A) They allow for rapidly developing action potentials in smooth muscle cells.
B) They are shallow invaginations of plasma membrane.
C) They maintain relatively constant tension in smooth muscle for a period of time.
D) They are part of the intracellular cytoskeleton.
E) They act as enzymes that remove phosphate from myosin.
160) What are caveolae?
A) Ion channels that allow for rapidly developing action potentials
B) Shallow invaginations of plasma membrane
C) Structures that allow for relatively constant tension maintained for a period of time
D) Parts of the intracellular cytoskeleton
E) Enzymes that removes phosphate from myosin
161) What is the role of myosin phosphatase?
A) To aid in rapidly developing action potentials
B) To form shallow invaginations of the plasma membrane
C) To maintain relatively constant tension for a period of time
D) To function as the intracellular cytoskeleton
E) To serve as an enzyme that removes phosphate from myosin
162) What is the role of pacemaker cells?
A) They rapidly develop action potentials.
B) They are shallow invaginations of the plasma membrane.
C) They maintain relatively constant tension for a period of time.
D) They are part of the intracellular cytoskeleton.
E) They are enzymes that remove phosphate from myosin.
163) A cancer patient is told by their physician that their colon is lacking smooth muscle tone. What does this mean?
A) The colon is developing action potentials too rapidly.
B) The colon has too many shallow invaginations of plasma membranes.
C) The colon is unable to maintain constant tension for sustained periods of time.
D) The intracellular cytoskeleton is overactive.
164) Cardiac muscle cells are like skeletal muscle cells in that they both
A) have striations.
B) depolarize as a result of Na+ and Ca2+ influxes.
C) possess intercalated disks.
D) lack sarcomeres.
E) are multinucleated.
165) Which of the following is NOT an age-related change in skeletal muscle?
A) Loss of muscle strength
B) Loss of synapse surface area
C) Loss of fast-twitch fibers
D) Decreased recovery time
E) Decrease in motor units
166) Curare blocks acetylcholine receptors at the motor end plate. This would result in
A) increased stimulation of the muscle.
B) more acetylcholinesterase production.
C) lack of Ca2+ uptake by the muscle fiber.
D) inability of the muscle fiber to respond to nervous stimulation.
E) sustained contraction of the muscle.
167) 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) Decreased release of acetylcholine from presynaptic neurons
B) Increased accumulation of acetylcholine in the synapse
C) Binding of the poison to acetylcholine receptors leading to inhibition of stimulation
D) Increased breakdown of acetylcholine in the synaptic cleft
E) Both increased accumulation of acetylcholine in the synapse and increased breakdown of acetylcholine in the synaptic cleft are correct.
168) One cause of spastic paralysis might be
A) inhibition of acetylcholine molecules.
B) blockage of acetylcholine receptors.
C) inhibition of acetylcholinesterase.
D) destruction of synaptic vesicles.
E) increase in the amount of acetylcholinesterase.
169) Which of the following occurs during recovery from oxygen deficit?
A) An elevated level of anaerobic metabolism
B) Depletion of reserves of creatine phosphate
C) Conversion of excess lactate to glucose
D) Glycogen degradation to provide creatine
E) Depressed level of aerobic respiration
170) Anabolic steroids can do all of the following except
A) increase muscle size and strength.
B) cause testicular atrophy.
C) cause cardiovascular disease.
D) increase the number of muscle fibers.
E) increase total muscle mass.
171) The condition of painful, spasmodic contractions of muscles is referred to as
A) cramps.
B) fibrositis.
C) fibromyalgia.
D) muscular dystrophy.
E) paralysis.
172) Inflammation of the fibrous connective tissue resulting in stiffness and soreness is
A) cramps.
B) fibrositis.
C) fibrosis.
D) muscular dystrophy.
E) paralysis.
173) Muscular dystrophy is characterized by
A) chronic muscle pain.
B) decreased size of muscle fibers.
C) spastic contractions of muscles.
D) replacement of muscle tissue by connective tissue.
E) hypertrophy of muscle tissue.
174) Which of the following is NOT true of muscular atrophy?
A) It is irreversible.
B) It can be caused by disuse.
C) It can be caused by denervation.
D) Transcutaneous stimulation can help prevent it.
E) Muscle fibers are replaced by connective tissue.
175) Which of the following is NOT a known effect of illegal use of anabolic steroids in large dosages?
A) Increased muscle size
B) Kidney damage
C) Diminished testosterone secretion
D) Increased cardiovascular fitness
E) Sterility
176) What does "A" represent on the diagram?
A) Myosin myofilament
B) Actin myofilament
C) Sarcomere
D) Z disk
E) Cross-bridge
177) What does "B" represent on the diagram?
A) Myosin myofilament
B) Actin myofilament
C) Sarcomere
D) Z disk
E) Cross-bridge
178) What does "C" represent on the diagram?
A) Myosin myofilament
B) Actin myofilament
C) Sarcomere
D) Z disk
E) Cross-bridge
179) What does "D" represent on the diagram?
A) Myosin myofilament
B) Actin myofilament
C) Sarcomere
D) Z disk
E) Cross-bridge
180) What does "E" represent on the diagram?
A) Myosin myofilament
B) Actin myofilament
C) Sarcomere
D) Z disk
E) Cross-bridge
181) What does "A" represent on the diagram?
A) Threshold
B) Depolarization
C) Depolarization phase of action potential
D) Repolarization phase of action potential
182) What does "B" represent on the diagram?
A) Threshold
B) Depolarization
C) Depolarization phase of action potential
D) Repolarization phase of action potential
183) What does "C" represent on the diagram?
A) Threshold
B) Depolarization
C) Depolarization phase of action potential
D) Repolarization phase of action potential
184) What does "D" represent on the diagram?
A) Threshold
B) Depolarization
C) Depolarization phase of action potential
D) Repolarization phase of action potential
185) The figure illustrates a detailed drawing of the neuromuscular junction. What does "B" represent?
A) Synaptic vesicles
B) Synaptic cleft
C) Sarcolemma
D) Presynaptic terminal
E) Postsynaptic membrane
186) The figure illustrates a detailed drawing of the neuromuscular junction. What does "A" represent?
A) Synaptic vesicles
B) Synaptic cleft
C) Sarcolemma
D) Presynaptic terminal
E) Postsynaptic membrane
187) The figure illustrates a detailed drawing of the neuromuscular junction. What does "C" represent?
A) Synaptic vesicles
B) Synaptic cleft
C) Sarcolemma
D) Presynaptic terminal
E) Postsynaptic membrane
188) The figure illustrates a detailed drawing of the neuromuscular junction. What does "D" represent?
A) Synaptic vesicles
B) Synaptic cleft
C) Sarcolemma
D) Presynaptic terminal
E) Postsynaptic membrane
189) The figure illustrates a detailed drawing of the neuromuscular junction. What does "E" represent?
A) Synaptic vesicles
B) Synaptic cleft
C) Sarcolemma
D) Presynaptic terminal
E) Postsynaptic membrane
190) What would result from a lack of extracellular Ca2+ at the neuromuscular junction?
A) Excessive synaptic vesicles would fuse and release too much ACh, overstimulating the myofiber.
B) Synaptic vesicles would fail to fuse and ACh would not be released.
C) Nothing would happen because extracellular Ca2+ does not play a role in muscle stimulation.
D) The neuron must use its intracellular Ca2+ to make the vesicles fuse.
E) Potassium ions are used in place of Ca2+ to ensure the vesicles fuse.
191) Consider a chemical that blocks the action of acetylcholinesterase. What effect does this have on muscles?
A) It would cause paralysis.
B) It would cause action potentials to be inhibited, thereby rendering the muscle useless.
C) The body would increase its production of acetylcholine to compensate.
D) The axons of the motor neurons would atrophy, and the muscle would weaken.
E) The muscle would have no way to relax, and spastic contractions would result.
192) A toxin released by the anaerobic bacterium Clostridium botulinum causes the food-borne illness known as botulism, which inhibits the release of ACh at the neuromuscular junction. What effect does this have on a person infected with the bacterium?
A) It causes flaccid paralysis, and if it affects the respiratory muscles, can result in death.
B) It disrupts the balance between ACh and acetylcholinesterase, leading to spastic contractions.
C) The brain compensates by producing more ACh, limiting the illness to only a few hours.
D) The jaws are most affected, and it results in "lockjaw."
E) Problems only result when the individual has low immunity.
193) Atrophy at the neuromuscular junction that naturally occurs with age would have what effect on muscles?
A) It would stimulate the nervous system to increase the speed in which it sends action potentials to the muscle fiber.
B) It would stimulate muscle cramps.
C) It would decrease the number of action potentials sent to the muscle fiber.
D) It would cause an increase in the amount of ACh released by the neurons to compensate.
E) It would have no effect on the muscles.
194) During a muscle fiber contraction, which of the following decreases in size? Check all that apply.
A) A band
B) Entire sarcomere
C) H zone
D) I band
195) In a contracted muscle, the A bands narrow because the length of the myosin myofilaments changes.
196) Which of the following are reasons that shivering raises body temperature? (Check all that apply.)
A) Shivering decreases warm blood flow to the core while increasing flow to the muscles.
B) Shivering depresses metabolism.
C) Shivering increases heat production up to 18 times that of resting levels.
D) The process of muscle contraction produces heat.
197) Why does muscle activity affect the temperature of the body?
A) The rate of chemical reactions increases in muscle fibers during contraction, so the rate of heat production also increases.
B) Muscle contraction generates pyrogens which reset the body's internal thermostat to a higher temperature.
C) Muscle activity directs more warm blood to the muscles away from the central core causing a cooling effect on your internal organs.
D) Increased muscle activity causes a rise in adipose stores which increases the insulation value of the body.
198) As muscle activity increases, the body temperature ________.
A) decreases
B) increases
199) Each ________ includes a Z disc and extends from each side of the Z disc to the ends of the myosin myofilaments.
A) anisotropic band or A band
B) isotropic band or I band
C) muscle fiber
D) sarcomere
200) The H zone
A) contains only myosin myofilaments.
B) contains only actin myofilaments.
C) contains both myosin and actin myofilaments.
201) Which of the following describes titin's roles in muscle contraction? (Check all that apply.)
A) Accounts for muscle's excitability
B) Accounts for muscle's extensibility and elasticity
C) Allows the sarcomere to recoil and stretch
D) Helps to hold the actin myofilaments in position
202) Excitation-contraction coupling begins with
A) the depolarization at the T tubules.
B) the production of an action potential in the sarcolemma.
C) the release of Ca2+ from the sarcoplasmic reticulum.
D) the release of the cross-bridge.
203) In order for excitation-contraction coupling to occur, the production of an action potential must occur within the ________ of a muscle fiber.
A) contraction
B) junction
C) sarcolemma
204) If all of the Ca2+ within a muscle fiber was removed, which of the following could still occur?
A) The heads of the myosin myofilaments would bind to G-actin to form cross-bridges.
B) An action potential that was produced at the neuromuscular junction would be propagated along the sarcolemma.
C) The troponin molecules bound to G actin molecules would be released, causing tropomyosin to move.
D) The heads of the myosin molecules would return to their resting position, and the recovery stroke would occur.
205) If one nerve stimulus arrives at a muscle fiber so soon that the fiber does NOT relax at all from the previous twitch, the most likely result will be ________.
A) fatigue
B) spasm
C) incomplete tetanus
D) complete tetanus
E) wave summation
206) Which muscle(s) can contract without the need for nervous stimulation?
A) Skeletal muscle only
B) Smooth muscle only
C) Cardiac muscle only
D) Smooth and cardiac muscle
E) Skeletal, smooth, and cardiac muscle
207) Which fibers are primarily responsible for producing lactate?
A) Slow fibers
B) Type IIA fast fibers
C) Type IIB fast fibers
D) Type I slow-twitch fibers
E) Red fibers
208) Michael Jordan was arguably the best player in professional basketball history. Scientifically, one would expect him to have highly developed ________ fibers.
A) red
B) white
C) intermediate
D) fast twitch
E) slow oxidative
209) Why is the contraction strength of smooth muscle relatively independent of its resting length?
A) It gets nearly all of its Ca2+ from the extracellular fluid.
B) It does not have intercalated discs.
C) It does not have sarcomeres.
D) It is regulated by a length-tension relationship.
E) It is involuntary muscle.
210) If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be ________.
A) fatigue
B) spasm
C) incomplete tetanus
D) complete tetanus
E) flaccid paralysis
211) Which of the following is true concerning isotonic eccentric contraction?
A) The muscle shortens, but tension remains constant.
B) The muscle lengthens, but tension remains constant.
C) The muscle tenses and shortens.
D) The muscle tenses, but length remains unchanged.
E) The muscle lengthens, and tension declines.
212) Which of the following is true concerning isotonic concentric contraction?
A) The muscle shortens, but tension remains constant.
B) The muscle lengthens, but tension remains constant.
C) The muscle tenses and shortens.
D) The muscle tenses, but length remains unchanged.
E) The muscle lengthens, and tension declines.
213) Athletes who train at high altitudes increase their red blood cell count, which increases their oxygen supply during exercise. Increased oxygen supply results in
A) increased glycolysis.
B) increased use of myokinase.
C) longer aerobic respiration.
D) longer anaerobic respiration.
E) reduced ATP consumption.
214) Which of the following would be caused by a contraction of smooth muscle?
A) Goose bumps
B) Blood leaving the left ventricle of the heart
C) Elevating the eyebrows
D) Blinking the eyelids
E) Deep inspiration
215) As you are lifting a box, someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle must
A) recruit more muscle fibers.
B) lower its threshold.
C) reduce its wave summation.
D) shift from isometric to isotonic contraction.
E) shift from slow-twitch to fast-twitch mode.
216) Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. How do you suppose these drugs work?
A) They prevent calcium from entering the sarcoplasmic reticulum of smooth muscle.
B) They stimulate the calcium pump in smooth muscle, thus removing calcium from the calmodulin.
C) They prevent calcium from exiting the sarcoplasmic reticulum in skeletal muscle.
D) They prevent calcium from entering cardiac muscle, thus slowing down the heart rate.
E) They prevent calcium from entering smooth muscle, thus allowing the muscle to relax.
217) Which of the following individuals would have more mitochondria in her skeletal muscle?
A) A 50-year-old sedentary computer programmer
B) A 22-year-old soccer player
C) A long-term hospice patient
D) A model on a reduced-calorie diet
E) A newborn
218) A skeletal muscle generates the greatest tension when it is
A) greatly stretched before being stimulated.
B) partially stretched before being stimulated.
C) fully relaxed before being stimulated.
D) well-rested and low in creatine phosphate.
E) high in lactate concentration.
219) A volleyball player depends on the gastrocnemius muscles for plantar flexion, whereas a marathon runner depends more on the soleus muscles for the same action. What characteristic of the soleus muscles makes this so?
A) They have smaller mitochondria.
B) They have more glycogen in them.
C) They don't have as many blood capillaries per gram of tissue.
D) They make more use of aerobic respiration.
E) They break ATP down to ADP and Pi faster.
220) The training regimen of a competitive weight lifter is designed partly to
A) convert certain muscles with parallel muscle fascicles into muscles with non-parallel muscle fascicles.
B) increase the average number of myofibrils per muscle fiber.
C) convert fast muscle fibers to slow muscle fibers.
D) increase the size of his motor units.
E) lower the threshold for muscle stimulation.
221) Which of the following statements best distinguishes between tetanus and treppe?
A) Tetanus is due to repeated stimulation of the muscle; treppe is the result of a single long stimulation of the muscle.
B) Tetanus occurs when stimulation of muscle occurs frequently with little to no relaxation between stimuli; treppe occurs when stimulation of muscle occurs frequently, but complete relaxation occurs between stimuli.
C) Tetanus only occurs in laboratory settings, but treppe occurs all the time in normal muscle activity.
D) Tetanus involves increasing the number of motor units stimulated simultaneously; whereas, treppe involves the repeated stimulation of a single muscle fiber.
222) Due to the pattern of innervation of skeletal muscle, one would expect that
A) there are fewer motor neurons than skeletal muscle fibers.
B) there are fewer muscle fibers than motor neurons.
C) the number of muscle fibers and motor neurons is equal.
223) Substance A is found to be a competitor with acetylcholine. Which step of muscle contraction physiology would be directly affected by this substance?
A) Exposure of the active sites on G actin
B) Release of acetylcholine from the presynaptic terminal
C) Generation of an action potential at the sarcolemma
D) Release of the myosin head following the power stroke
224) Whales are air-breathing aquatic mammals, and some species can remain underwater for long periods of time. Which type of skeletal muscle fibers are most likely dominant in these deep diving whales?
A) Slow fibers
B) Fast (type IIa) fibers
C) Fast (IIb) fibers
D) White fibers
225) Which of the following descriptions best represents the appearance of the sarcomere during peak contraction?
A) The H zone is eliminated, and the I bands are very thin.
B) The width of the A band is slightly less than the width of the I band.
C) The H zone is equivalent to one-third of the length of the A band.
D) The I bands and A bands are of equal widths.
226) Which of the following statements best predicts the effect of a substance that blocks creatine kinase activity?
A) ATP production from creatine phosphate would decrease.
B) ATP production from creatine phosphate would increase.
C) ADP production from creatine phosphate would decrease.
D) ADP production from creatine phosphate would increase.
227) Calcium ion blocking agents would most likely affect
A) action potential propogation along the transverse tubules.
B) release of Ca2+ from the sarcoplasmic reticulum.
C) movement of the tropomyosin molecule.
D) release of the myosin head from the G actin molecule.
228) Myasthenia gravis results from the destruction of acetylcholine receptors at the neuromuscular junction, but treatment involves medications that reduce acetylcholinesterase activity. Which statement best explains the effectiveness of these medications?
A) The antibodies destroy some but not all of the acetylcholine receptors, so reducing acetylcholinesterase activity increases the likelihood that acetylcholine will bind to the remaining receptors.
B) Acetylcholinesterase is the substance that destroys the receptors as well, so reducing its activity increases the number of acetylcholine receptors.
C) Acetylcholinesterase breaks down the acetylcholine to a substance that can bind to the damaged receptors.
D) The antibodies that destroy the acetylcholine receptors are less likely to work if acetylcholinesterase is present.
229) Diseases that affect the ability of skeletal muscle to contract are considered life threatening because
A) the movement of blood through the blood vessels of the body depends solely on skeletal muscle contractions.
B) respiratory movements depend on skeletal muscle contractions.
C) movement of food through the digestive tract depends on skeletal muscle contractions.
D) All of the choices are correct.
230) Which of the following is not an important function of calcium ions in skeletal muscle activity?
A) Depolarization of the sarcolemma
B) Release of acetylcholine from the presynaptic terminal
C) Exposure of the active sites on G actin
D) All of these are important functions of calcium ions in skeletal muscle contraction.
231) Which of the following statements does not accurately describe factors that determine the amount of force generated during a muscle contraction?
A) The number of cross-bridges that can form is higher in a short muscle fiber compared to longer fibers.
B) Muscle fibers that have larger diameters have more myofibrils and therefore can form more cross-bridges.
C) Increasing stimulation of a muscle fiber results in increased formation of cross-bridges.
D) Muscle fibers that are stretched to the optimal length will provide higher numbers of cross-bridges.
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Seeley’s Anatomy and Physiology 12e Complete Test Bank
By Cinnamon VanPutte