Term
. Muscles which move a limb away the midline of the body are termed
A. abductor muscles.
B. adductor muscles.
C. extensor muscles.
D. flexor muscles. |
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Definition
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Term
. A muscle that constricts an opening is a/an
A. extensor.
B. levator.
C. antagonist.
D. sphincter. |
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Definition
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Term
The prime mover of any skeletal movement is called the
. flexor.
B. agonist.
C. abductor.
D. antagonist |
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Definition
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Term
Each fascicle of a muscle is surrounded by the
A. perimysium.
B. epimysium.
C. endomysium. |
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Definition
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Term
The light band of a skeletal muscle is known as the
A. A band.
B. Z disc.
C. I band.
D. H zone. |
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Definition
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Term
Duchenne's muscular dystrophy
A. is an X-linked recessive trait.
B. most often affects women.
C. involves degeneration of the smooth muscle dense bodies.
D. All of the choices are correct. |
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Definition
| is an X-linked recessive trait. |
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Term
Somatic motor neurons release the neurotransmitter _________ at the neuromuscular junction.
A. dopamine
B. acetylcholine
C. norepinephrine
D. serotonin |
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Definition
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Term
. Each somatic motor neuron with all the muscle fibers it innervates is a
A. fascicle.
B. varicosity.
C. motor unit.
D. sarcolemma |
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Definition
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Term
Subunits of skeletal muscle cells that are composed of sarcomeres are called
A. myofibrils.
B. myofilaments.
C. sarcolemmas.
D. transverse tubules. |
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Definition
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Term
What structure is composed of protein filaments and is located in the center of the thick filaments?
A. Z disk
B. titin
C. M line
D. actin |
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Definition
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Term
What structure runs the length of the sarcomere through the thick filaments and contributes to the elastic recoil in muscle?
A. Z disk
B. titin
C. M line
D. actin |
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Definition
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Term
What structure runs from Z line to Z line?
A. A band
B. I band
C. sarcomere
D. myofibril |
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Definition
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Term
. Myosin contains binding sites for ______________ and ______________.
A. sodium, calcium.
B. troponin, ATP.
C. ATP, actin.
D. actin, calcium |
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Definition
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Term
During skeletal muscle contraction, adjacent _________ are pulled closer together as the _______ between them shorten.
A. A bands; I bands
B. I bands; A bands
C. Z disks; A bands
D. Z disks; I bands |
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Definition
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Term
During skeletal muscle contraction,
A. the H zone increases in size.
B. Ca2+ associates with tropomyosin.
C. myosin heads interact with tropomyosin.
D. thin filaments slide across thick filaments. |
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Definition
| D. thin filaments slide across thick filaments. |
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Term
Which of the following does NOT occur during the cross bridge cycle?
A. a second ATP binding causes cross bridges to form.
B. ADP is released at the end of the power stroke.
C. energized myosin heads bind troponin. |
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Definition
| C. energized myosin heads bind troponin. |
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Term
The _________ complex contains three proteins designated as the I, T, and C types.
A. actin
B. myosin
C. tropomyosin
D. troponin |
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Definition
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Term
The movement of the troponin-tropomyosin complex requires
A. ATP.
B. Ca2+.
C. Acetylcholine.
D. Na+. |
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Definition
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Term
The Ca2+ required for skeletal muscle contraction
A. is released from the sarcoplasmic reticulum.
B. enters the cell due to the opening of voltage regulated Ca2+ channels from the T tubules.
C. is actively transported into the cell.
D. is released from mitochondria. |
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Definition
| A. is released from the sarcoplasmic reticulum. |
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Term
. The pumps that actively transport calcium back into the _______ are called Ca2+ -ATPase pumps.
A. transverse tubules
B. sarcoplasmic reticulum
C. neuromuscular junction
D. None of the choices are correct. |
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Definition
| B. sarcoplasmic reticulum |
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Term
Which of the following is NOT true of the relaxation of a muscle fiber?
A. ATP is needed to fuel the calcium pumps
B. calcium release channels close
C. the action potential must continue
D. Ca2+ moves from the sarcoplasm to the sarcoplasmic reticula |
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Definition
| C. the action potential must continue |
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Term
The inability of muscle cells to relax due to high frequency stimulation is termed
A. treppe.
B. recruitment.
C. twitch.
D. tetanus. |
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Definition
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Term
. _______ refer to muscle contractions that produce a shortening muscle with a constant contraction strength at a given load.
A. Treppe contractions
B. Isotonic contractions
C. Twitch contractions
D. Isometric contractions |
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Definition
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Term
Which of the following statements about muscles is FALSE?
A. During isometric contractions muscles do not generate tension.
B. The strength of contraction is directly proportional to the stimulus intensity.
C. Tendons act as part of the series-elastic component of a muscle.
D. During muscle contraction the Z disks move closer together. |
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Definition
| A. During isometric contractions muscles do not generate tension. |
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Term
A muscle contraction against a resistance that is greater than the force and causes muscle lengthening is a(n)
A. concentric contraction.
B. isometric contraction.
C. eccentric contraction.
D. isokinetic contraction. |
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Definition
| C. eccentric contraction. |
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Term
A shortening of the muscle that occurs when the tension is greater than the load is a(n)
A. concentric contraction.
B. isometric contraction.
C. eccentric contraction.
D. isokinetic contraction. |
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Definition
| A. concentric contraction. |
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Term
Which of the following is NOT true about the series-elastic component to contraction?
A. It absorbs some of the tension of muscle contraction.
B. It provides for elastic recoil when muscles relax.
C. It must loosen for a muscle to shorten.
D. It is provided by tendons. |
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Definition
| C. It must loosen for a muscle to shorten. |
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Term
Which of the following does NOT increase the strength of the muscle contraction?
A. a high number of fibers stimulated
B. increased frequency of stimulation
C. thicker muscle fiber
D. resting sarcomere length of 3.6µm |
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Definition
| D. resting sarcomere length of 3.6µm |
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Term
. In regards to the relationship between resting muscle fiber length and tension generated
A. maximal tension is generated when the thick and thin filaments slightly overlap.
B. maximal tension is generated when the thick and thin filaments do not overlap.
C. maximal tension is generated when the thick and thin filaments greatly overlap.
D. the amount of overlap is unimportant in determining maximal tension. |
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Definition
| A. maximal tension is generated when the thick and thin filaments slightly overlap. |
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Term
. Skeletal muscles at rest obtain most of their energy from the aerobic respiration of
A. glucose.
B. protein.
C. fatty acids.
D. glycogen. |
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Definition
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Term
ATP in muscle contraction is needed for
A. attachment of myosin cross bridges to actin.
B. release of myosin cross bridges from actin.
C. pumping of Ca2+ back into the sarcoplasmic reticulum.
D. All of the choices are correct. |
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Definition
| D. All of the choices are correct. |
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Term
Which of the following is true under heavy exercise in for the first 30 minutes of activity heavy exercise?
A. Most energy is derived from glycogen and plasma glucose.
B. The percentage of energy obtained from plasma free fatty acids exceeds that of mild exercise.
C. The percentage of energy obtain from plasma glucose is less than that of moderate exercise.
D. All of the choices are correct. |
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Definition
| A. Most energy is derived from glycogen and plasma glucose. |
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Term
Fatty acids provide the majority of the energy for muscle metabolism when a person is
A. exercising at 25% of VO2max.
B. exercising at 50% of VO2max.
C. exercising at 75% of VO2max.
D. exercising at 100% of VO2max. |
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Definition
| A. exercising at 25% of VO2max. |
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Term
The first 1 to 2 minutes of moderate to heavy exercise relies on _____ for ATP production.
A. aerobic respiration of glucose
B. anaerobic respiration of glucose
C. aerobic respiration of fatty acids
D. anaerobic respiration of amino acids |
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Definition
| B. anaerobic respiration of glucose |
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Term
. Repaying the oxygen debt requires replacing oxygen that was
A. bound to blood hemoglobin.
B. bound to muscle myoglobin.
C. used for tissue warm up.
D. All of the choices are correct. |
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Definition
| D. All of the choices are correct. |
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Term
A reserve of high energy phosphate is stored in muscle as
A. phosphocreatine.
B. adenosine triphosphate.
C. glucose 6-phosphate.
D. creatine kinase. |
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Definition
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Term
. Slow twitch fibers have a ______ oxidative capacity and ________ glycogen content.
A. high, high
B. high, low
C. low, low
D. low, high |
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Definition
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Term
Type I skeletal muscle fibers
A. contract rapidly.
B. have a large diameter.
C. have a low myoglobin concentration.
D. have numerous mitochondria. |
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Definition
| D. have numerous mitochondria. |
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Term
Central fatigue is caused by
A. decreased H+ concentration in the muscle cells.
B. increased glycogen in muscle cells.
C. changes in the CNS.
D. All of the choices are correct. |
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Definition
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Term
Which of the following is NOT a contributing factor to skeletal muscle fatigue?
A. increased intracellular K+
B. depletion of intracellular K+
C. accumulation of extracellular K+
D. accumulation of cytoplasmic Pi |
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Definition
| A. increased intracellular K+ |
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Term
The amount of fat stored in skeletal muscles will be ______________ by endurance training.
A. increased
B. decreased
C. unchanged |
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Definition
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Term
. Endurance training results in increased
A. muscle mitochondria number.
B. glycogen depletion during exercise.
C. number of type IIB fibers.
D. lactate production per unit time. |
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Definition
| A. muscle mitochondria number. |
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Term
The greater the level of physical training, the higher the proportion of energy derived from the oxidation of ____ during exercise below VO2max.
A. glucose
B. protein
C. amino acids
D. fatty acids |
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Definition
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Term
Muscle hypertrophy is due to
A. increased number of myofibrils in the muscle fiber.
B. increased number of muscle fibers.
C. increased size of the myofibrils.
D. Both increased number of myofibrils in the muscle fiber and increased size of the myofibrils are correct. |
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Definition
| Both increased number of myofibrils in the muscle fiber and increased size of the myofibrils are correct. |
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Term
Myostatin is
A. a paracrine regulator that inhibits muscle growth.
B. a paracrine regulator that stimulates muscle growth.
C. an autocrine regulator that inhibits muscle growth.
D. an autocrine regulator that stimulates muscle growth. |
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Definition
| A. a paracrine regulator that inhibits muscle growth. |
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Term
Muscle repair is due to ____ forming myotubes that fuse to form new muscle fibers.
A. satellite cells
B. myofibrils
C. muscle cells
D. All of the choices are correct. |
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Definition
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Term
Degeneration of ______________ motor neurons occurs in amyotrophic lateral sclerosis.
A. upper
B. middle
C. lower
D. both middle and lower |
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Definition
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