Q&A Hero

Q: Which of the following statements regarding cardiac muscle is true? A. Dense bodies anchor thin filaments. B. Fibers lack I and A bands. C. Intercalated discs contain gap junctions. D. Fibers lack branches.

Q: The inhibition of an antagonistic muscle so that the agonist can do the intended movement is due to A. crossed-extensor reflex. B. monosynaptic reflex. C. reciprocal innervation. D. flaccid paralysis.

Q: Regulation of motor neurons involves the actions of the basal nuclei and cerebellum.

Q: The cerebellum directly influences motor activity.

Q: The cerebellar influence on motor activity is excitatory.

Q: Hemiplegia is paralysis of an upper limb of one side and the lower limb of the other side.

Q: Damage to upper motor neurons would be indicated by all of the following except A. spastic paralysis. B. chorea. C. intention tremor. D. flaccid paralysis.

Q: The pyramidal tracts include the __________ and _____________ tracts. A. rubrospinal, lateral corticospinal B. reticulospinal, ventral corticospinal C. ventral corticospinal, lateral corticospinal D. rubrospinal, reticulospinal

Q: Parkinson's disease involves degeneration of nerve fibers from the A. red nucleus. B. substantia nigra. C. cerebellum. D. corpus callosum.

Q: Random uncontrolled contractions of different muscle groups as a result of damage to the basal nuclei is a symptom of upper motor neuron damage called A. intention tremor. B. Babinski's reflex. C. chorea. D. resting tremor.

Q: An individual suffering damage to the basal nuclei resulting in a lack of desire to use a limb would be suffering from A. Parkinson's disease. B. chorea. C. intention tremor. D. akinesia.

Q: Excitation of the Golgi tendon organ normally induces A. contraction of a muscle's extrafusal fibers. B. relaxation of a muscle's extrafusal fibers. C. contraction of a muscle's intrafusal fibers. D. relaxation of a muscle's intrafusal fibers.

Q: A crossed-extensor reflex demonstrates double reciprocal innervation.

Q: Muscle spasms can be avoided by stretching slowly, which stimulates mainly the primary, annulospiral sensory endings.

Q: Alpha motoneurons innervate A. nuclear chain fibers. B. nuclear bag fibers. C. extrafusal fibers. D. intrafusal fibers.

Q: The stretch reflex is enhanced in response to activation of A. the Golgi tendon organ. B. alpha motoneurons. C. gamma motoneurons. D. lower motoneurons.

Q: Coactivation of alpha and gamma motoneurons is stimulated by ______________ neurons. A. upper motor B. lower motor C. intermotor D. sensory

Q: Activation of intrafusal fibers by alpha motoneurons creates muscle tone.

Q: The monosynaptic stretch reflex involves the actions of the muscle spindles.

Q: Clonus is a flapping motion caused by alternate activation of antagonistic stretch reflexes.

Q: The ______________ reflex prevents excessive muscle contraction. A. flexor B. cross-extensor C. Golgi tendon D. muscle spindle

Q: Damage to the lower motor neurons would induce A. spastic paralysis. B. clonus. C. Babinski's sign. D. flaccid paralysis.

Q: Degeneration of ______________ motor neurons occurs in amyotrophic lateral sclerosis. A. upper B. middle C. lower D. both middle and lower

Q: Lower motor neurons are found in the lower part of the brain.

Q: Damage to the __________ nerve root would prevent the muscle spindle from transmitting information to the central nervous system. dorsal B. ventral

Q: Primary, annulospiral endings are found associated with A. the nuclear bag fibers. B. the extrafusal fibers. C. the mossy fibers. D. the basal nuclei.

Q: The muscle spindle apparatus is associated with A. extrafusal fibers. B. tendons. C. intrafusal fibers. D. Golgi tendon organs.

Q: What type of sensory neuron is associated with a muscle spindle apparatus? A. primary, annulospiral sensory endings B. pyramidal sensory endings C. secondary, flower-spray sensory endings D. Both primary, annulospiral sensory endings and secondary, flower-spray sensory endings are correct.

Q: The muscle spindle apparatus serves as a muscle length detector.

Q: Matching Questions Formation of new sarcomeres and growth of myofibrils requires which of the following proteins? A. titin B. nebulin C. obscurin D. All apply.

Q: Muscle repair is due to ____ forming myotubes that fuse to form new muscle fibers. A. satellite cells B. myofibrils C. muscle cells D. All apply.

Q: Matching Questions 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 apply.

Q: Matching Questions 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 PO43-

Q: Fatigue appears to occur due to the reduced ability of the sarcoplasmic reticulum release of Ca2+ with neural stimulation.

Q: Endurance training increases the oxidative capacity of a muscle cell.

Q: The amount of fat stored in skeletal muscles will be ______________ by endurance training. increased B. decreased C. unchanged

Q: Matching Questions Endurance training results in increased A. muscle mitochondria number. B. glycogen depletion during exercise. C. number of type IIX fibers. D. lactate production per unit time.

Q: Matching Questions 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

Q: Matching Questions The decline in physical strength of older persons is due to A. decreased size of fast-twitch fibers. B. reduced density of blood capillaries. C. reduced muscle mass. D. All apply.

Q: Matching Questions 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.

Q: Matching Questions Myostatin is A. a paracrine regulator that inhibits satellite cell function and muscle growth. B. a paracrine regulator that stimulates satellite cell function and muscle growth. C. an autocrine regulator that inhibits satellite cell function and muscle growth. D. an autocrine regulator that stimulates satellite cell function and muscle growth.

Q: Matching Questions Type I skeletal muscle fibers A. contract rapidly. B. have a large diameter. C. have a low myoglobin concentration. D. have numerous mitochondria.

Q: Matching Questions Type IIX skeletal muscle fibers A. generate less tension than type IIA fibers. B. fatigue very slowly. C. generate more tension than type I fibers. D. have a high myoglobin concentration.

Q: Matching Questions The fastest shortening muscle fiber in humans is the A. type IIA. B. type IIB. C. type IIX. D. type I.

Q: Matching Questions Muscle fatigue A. occurs when muscles are only partially able to contract. B. occurs when muscle cell glycogen is depleted. C. occurs when muscle cell pH increases. D. occurs due to decreased extracellular K+.

Q: Matching Questions Which of the following is NOT true of slow oxidative/Type I red muscle fibers? A. small diameter B. high resistance to fatigue C. high amount of myosin ATPase present D. slow twitch rate

Q: Matching Questions Which of the following is true of fast oxidative, Type IIA muscle fibers? A. many capillaries B. anaerobic C. low myoglobin content D. small diameter

Q: Matching Questions Which of the following is NOT true of fast glycolytic/Type IIX white muscle fibers? A. high glycogen content B. few capillaries C. low oxidative capacity D. aerobic

Q: Matching Questions Slow twitch fibers have a ______ oxidative capacity and ________ glycogen content. A. high, high B. high, low C. low, low D. low, high

Q: Matching Questions 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 apply.

Q: Exceeding the VO2max will result in lactate production by the muscle.

Q: Matching Questions Which of the following is true for the first 30 minutes of 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 apply.

Q: Matching Questions Blood lactate will begin to rise when exercise is performed at a rate that is A. 15% of VO2max. B. 25% of VO2max. C. 50% of VO2max. D. 85% of VO2max.

Q: Matching Questions 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.

Q: Matching Questions 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

Q: Matching Questions Repaying the oxygen debt requires replacing oxygen that was A. bound to blood hemoglobin and muscle myoglobin. B. needed to metabolize lactic acid. C. used for tissue warm up. D. All apply.

Q: Matching Questions A reserve of high energy phosphate is stored in muscle as A. phosphocreatine. B. adenosine triphosphate. C. glucose 6-phosphate. D. creatine kinase.

Q: Matching Questions An increase in plasma creatine phosphokinase could indicate A. muscular dystrophy. B. liver disease. C. heart attack. D. Both muscular dystrophy and heart attack.

Q: Fast twitch fibers have the greatest resistance to fatigue.

Q: Matching Questions Insertion of ______________ in the muscle cell membrane increases cellular glucose uptake. A. GLUT1 B. GLUT2 C. GLUT3 D. GLUT4

Q: Matching Questions Skeletal muscles at rest obtain most of their energy from the aerobic respiration of A. glucose. B. protein. C. fatty acids. D. glycogen.

Q: Matching Questions 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.

Q: Matching Questions 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.

Q: Matching Questions 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.

Q: Matching Questions 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 3.6m

Q: Matching Questions 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.

Q: High-energy phosphates are stored in skeletal muscle as creatine phosphate.

Q: Increasing the frequency of action potentials in a somatic motor neuron will induce increased force of muscle contraction.

Q: Matching Questions The inability of muscle cells to relax due to high frequency stimulation is termed A. treppe. B. recruitment. C. twitch. D. tetanus.

Q: Matching Questions The staircase effect or _____ represents a warm up effect due to increasing intracellular calcium concentrations. A. treppe B. tetanus C. incomplete tetanus D. tonus

Q: Smooth, sustained muscle contractions in vivo are due to synchronous activation of motor units.

Q: For a muscle to contract, it must overcome stronger opposing forces.

Q: Isotonic muscle contractions are often preceded by isometric contractions.

Q: Matching Questions When a muscle cell generates tension but does not shorten, a(n) ______ contraction occurs. A. isometric B. isotonic C. spastic D. flaccid

Q: Matching Questions _______ 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

Q: Matching Questions A force-velocity curve shows the _______ relationship between the force opposing muscle contraction and the velocity of muscle shortening. A. direct B. inverse C. increased D. no

Q: Matching Questions 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.

Q: Matching Questions The actin filament is a polymer formed from 300 to 400 globular subunits called A. I-actin. B. T-actin. C. G-actin. D. C-actin.

Q: Transverse tubules contain voltage-gated calcium channels that respond to membrane depolarization and are directly coupled to the calcium release channels in the sarcoplasmic reticulum.

Q: Matching Questions 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.