A&P Ch 8 Muscles

25 July 2022
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question
Which muscle cells have the greatest ability to regenerate? a) skeletal b) cardiac c) smooth d) no muscle can regenerate
answer
c) smooth
question
Most skeletal muscle contain ___. a) muscle fibers of the same type b) a mixture of fiber types c) a predominance of slow oxidative fibers d) a prejdominance of fast oxidative fibers
answer
b) a mixture of fiber types
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Fatigued muscle cells that recover rapidly are the products of ___. a) intense exercise of long duration b) intense exercise of short duration c) slow exercise of long duration d) slow exercise of short duration
answer
b) intense exercise of short duration
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The strongest muscle contractions are normally achieved by ___. a) increasing stimulus above the threshold b) increasing stimulus above the treppe stimulus c) increasing the stimulation up to the maximal stimulus d) recruiting small and medium muscle fibers
answer
c) increasing the stimulation up to the maximal stimulus
question
Which of the following would be crecuited later in muscle stimulation when contractile strength increases? a) motor units with the longest muscle fibers b) many small motor units with the ability to stimulate other motor units c) large motor units with small, highly excitable neurons d) motor units with larger, less excitable neurons
answer
d) motor units with larger, less excitable neurons
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Which of the following is "not" a result of resistance exercise? a) increase in the efficiency of the respiratory system b) increase in the efficiency of the circulatory system c) increase in the number of muscle cells d) increase in thenumber of myofibrils within the muscle cells
answer
c) increase in the number of muscle cells
question
Excitation-contraction coupling requires which of the following substances? a) Ca2+ and ATP b) Ca2+ only c) ATP only d) ATP and glucose
answer
a) Ca2+ and ATP
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Which of the following is a factor that affects the velocity and duration of muscle contraction? a) number of muscle fibers stimulated b) size of the muscle fibers stimulated c) load on the fiber d) muscle length
answer
c) load on the fiber
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Myoglobin ___. a) breaks down glycogen b) is a protein involved in the direct phosphorylation of ADP c) stores oxygen in muscle cells d) produces the end plate protential
answer
c) stores oxygen in muscle cells
question
What structure in skeletal muscle cells functions in calcium storage? a) sacroplasmic reticulum b) mitochondria c) intermediate filament network d) myofibrillar network
answer
a) sacroplasmic reticulum SR is an elaborate smooth endoplasmic reticulum. Its interconnecting tubules surrounds each myofibril the way a sleeve surrounds your arm.
question
What does oxygen deficit reporesent? a) amount of energy needed for exertion b) the differnce between the amount of oxygen needed for totally aerobic muscle activity and the amound actually used. c) the amount of oxygen taken into the body prior to exertion d) the amount of oxygen taken into the body immediatly after the exertion
answer
b) the differnce between the amount of oxygen needed for totally aerobic muscle activity and the amound actually used.
question
Immediately following the arival of the stimulus at a skeletal muscle cell there is a short period called the ___ period during which the events of excitation-contraction coupling occur. a) contraction b) relaxation c) latent d) refractory
answer
c) latent Latent period - the first few millaseconds following stimulation when excitation-contraction coupling is occuring.
question
Creatine phosphate functions in themuscle cell by ___. a) forming a temporary chemical compound with myosin b) forming a chemical compound with actin c) inducing a conformational change in the myofilaments d) storing energy that will be transferred to ADP to resynthesize ATP
answer
d) storing energy that will be transferred to ADP to resynthesize ATP
question
What controls the force of muscle contraction? a) wave summation b) multimotor unit summation c) treppe d) concentric contractions
answer
b) multimotor unit summation Recruitment also called multimotor unit summation. Recruitment is achieved by delivering shocks of increasing voltage to the muscle, calling more and more muscle fibers into play.
question
The major function of the sarcoplasmic reticulum in muscle contraction is to ___. a) make and store phosphocreatine b) synthesize actin and myosin myofilaments c) provide a source of myosin for the contraction process d) regulate intracellular calcium concentration
answer
d) regulate intracellular calcium concentration
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What produces the striations of a skeletal muslce cell? a) a difference in the thickness of the sarcolemma b) the arrangement of myofilaments c) the sarcoplasmic reticulum d) the T tubules
answer
b) the arrangement of myofilaments
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Which of the following are composed of myosin? a) thick filaments b) thin filaments c) all myofilaments d) Z discs
answer
a) thick filaments Thick filaments containing myosin (red). Thin filaments containing actin (blue).
question
During muscle contraction, myosin across bridges attach to which active sites? a) myosin filaments b) actin filaments c) Z discs d) thick filaments
answer
b) actin filaments
question
Which of the following surrounds the individual muscle cells? a) perimysium b) endomysium c) epimysium d) fascicle
answer
b) endomysium Endomysium = within the muscle. Is a whispy sheath of connective tissue that surrounds each individual muscle fiber.
question
Smooth muscles taht act like skeletal muscles but are controlled by autonomic nerves and hormones are ___. a) single-unit muscles b) multiunit muscles c) red muscles d) white muscles
answer
b) multiunit muscles
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Rigor mortis occurs because ___. a) the cells are dead b) sodium oions leak out of the muscle c) no ATP is available to release attached actin and myosin molecules d) proteins are beginning to break down, thus preventing a flow of calcium ions
answer
c) no ATP is available to release attached actin and myosin molecules
question
Which of the choices below does "not" describe how recovery oxygen uptake (oxygen deficit) restores metabolic conditions? a) converts lactic acid back into glycogen stores in the liver b) resynthesizes creatine phosphate and ATP in muscle fibers c) increases the level of lactic acid in the muscle d) replaces the oxygen removed from myoglobin
answer
c) increases the level of lactic acid in the muscle
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The term aponeurosis refers to ___. a) the bands of myofibrils b) a sheetlike indirect attachment to a skeletal element c) the rough endoplasmic reticulum d) the tropomyosin-troponin complex
answer
b) a sheetlike indirect attachment to a skeletal element
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The oxygen-binding protein found in muscle cells is ___. a) hemoglobin b) ATP c) myoglobin d) immunoglonin
answer
c) myoglobin
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The contractile units of skeletal muscles are ___. a) microtubules b) mitochondria c) T tubules d) myofibrils
answer
d) myofibrils
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Which of the following is "not" a way muscle contractions can be graded? a) changing the frequency of stimulation b) changing the strength of the stimulas c) changing the type of muscle fibers involved in the contraction d) changing the type of neurotransmitter released by the motor neuron
answer
c) changing the type of muscle fibers involved in the contraction
question
What is the functional unit of a skeletal muscle called? a) a sarcromere b) a myofilament c) a myofibril d) the sarcoplasmic reticulum
answer
a) a sarcomere
question
What is the functional role fo theT tubules? a) stabilize the G and F actin b) enhance cellular communication during muscle contraction c) hold cross bridges in place in a resting muscle d) synthesize ATP to provide energy for muscle contraction
answer
b) enhance cellular communication during muscle contraction
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What is the role of calcium ions in muslce contraction? a) form hydoxyapatite cyrstals b) reestablish glycogen stores c) bind to regulatory sites on troponin to remove contraction inhibition d) increase levels of myoglobin
answer
) bind to regulatory sites on troponin to remove contraction inhibition
question
The warm-up period required of athletes in order to bring their muscles to peak performance is called ___. a) twitch b) wave summation c) treppe d) incomplete tetanus
answer
c) treppe
question
The main effect of the warm-up period of athletes, as the muscle contractions increase in strenth, is to ___. a) increase the myoglobin content b) convert glycogen to glucose c) tone the muscles and stabilize the joints for the workout d) enhance the availability of calcium and the efficiency of enzyme systems
answer
d) enhance the availability of calcium and the efficiency of enzyme systems
question
During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for engery. As a result, the pyruvic acid is converted to ___. a) a strong base b) stearic acid c) hydorchloric acid d) lactic acid
answer
d) lactic acid When muscles contract vigorously and contractile activity reaches about 70% of the maximum possible (anerobic conditions), most of the pyruvic acid produced during glycolysis is converted into lactic acid, and the overall process is referred to as anaerobic glycolysis.
question
When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods? a) relaxation period b) refractory period c) latent period d) fatigue period
answer
b) refractory period During repolarization, a muscle fiber is in the refractory period, because the cell cannot be stimulated again until repolarization is complete. Repolarization - the sarcolemma is restored to its initial polarized state. sarcolemma = plasma membrane
question
In an isotonic contraction, the muscle ___. a) changes in length and moves the "load" b) does not change in length but increases tension c) never converts pyruvate to lactate d) rapidly resynthesizes creatine phosphate and ATP
answer
a) changes in length and moves the "load"
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The muscle cell membrane is called the ___. a) endomysium b) sarcolemma c) perimysium d) epimysium
answer
b) sarcolemma
question
Which of the following is the correct sequence of events for muscle contractions? a) motor neuron action potential, meurotransmitter release, muscle cell action potential, release of calcium ions from SR, AtP-driven power stroke, sliding of myofilaments b) neurotransmitter release, muscle cell action potential, motor reuron action potential, release of calcium ions from SR, sliding of myofilaments, ATP-driven power stroke c) muslce cell action potential, neurotransmitter release, atp-driven power stroke, calcium ion release from SR, sliding of myofilaments d) neurotransmitter rlease, motor neuron cation potential, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke
answer
a) motor neuron action potential, meurotransmitter release, muscle cell action potential, release of calcium ions from SR, AtP-driven power stroke, sliding of myofilaments
question
The mechanism of contraction in smooth muscle is different from skeletal muscle in that ___. a) actin and myosin interact by the sliding filament mechanism b) the trigger for contraction is a rise in intracellular calcium c) the site of calcium regulation differs d) ATP energizes the sliding process
answer
c) the site of calcium regulation differs
question
Which of the following describes the cells of single-unit visceral muscle? a) they contract all at once. b) They are chemically coupled to one another by gap junctions. c) they exhibit spontaneous action potentials. d) They consist of muscle fibers that are structurally independent of each other.
answer
c) they exhibit spontaneous action potentials.
question
Whic of the following is not a role of ionic calcium in muscle contraction? a) triggers neurotransmitter secretion b) promotes contraction inhibitor c) removes contraction inhibitor d) activates epinephrine released from adrenal gland
answer
d) activates epinephrine released from adrenal gland
question
Which of the following is true about smooth muscle contraction? a) Certain smooth muscle cells can actually divide to increase their numbers. b) Smooth muscle, in contrast to skeletal muscle, cannot synthesize or secrete any connective tissue elements. c) Smooth muscle cannot stretch as much as skeletal muscle. d) Smooth muslce has well-developed T tubules a the site of invagination.
answer
a) Certain smooth muscle cells can actually divide to increase their numbers.
question
Smooth muscle is charaterized by all of the following except ___. a) it appears to lack troponin b) there are more thick filaments than thin filaments c) there are no sarcomeres d) there are noncontractile intermediate filaments taht attach to dense bodies within the cell
answer
b) there are more thick filaments than thin filaments
question
Muscle tissue has all of the following properties except ___. a) secretion b) contractility c) extensibility d) excitability
answer
a) secretion
question
The giant protein titin maintains the orgainzation of the ___ assisting in muscle stretching. a) A band b) I band c) Z disc d) M line
answer
a) A band
question
Which of the following statements is true? a) Cardiac muscle cells have many nuclei. b) Smooth muscle cells have T tubules. c) Striated muscle cells are long and cylindrical with many nuclei. d) Cardiac muscle cells are found in the heart and large blood vessels.
answer
c) Striated muscle cells are long and cylindrical with many nuclei.
question
An enaerobic metabolic pathway that results in the productionof two net ATPs per glucose plus tow pyruvic acid molecules is ___. a) the citric acid cycle b) glycolysis c) hydrolysis d) the electron transport chain
answer
b) glycolysis
question
Muslce tone is ___. a) the ability of a muscle to efficiently cause skeletal movements b) the feeling of well-being following exercise c) a state of susteained partial contraction d) the condition of athletes after intensive training
answer
c) a state of susteained partial contraction
question
The sliding filament model of contraction involves ___. a) actin and myosin sliding past each other and partially overlapping b) the shortening of thick filaments so that thin filaments slide past c) actin and myosin shortening but not sliding past each other d) the Z discs sliding over the myofilaments
answer
a) actin and myosin sliding past each other and partially overlapping
question
After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction? a) calcium ions returning to the terminal cisternae b) the tropoyosin blocking the myosin once full contraction is achieved c) acetylcholinesterase destroying the ACh d) the actin potential stips going down the overloaded T tubules
answer
c) acetylcholinesterase destroying the ACh
question
Which of the following statements is most accurate? a) Muscle tension remains relatively constant during isotonic contraction. b) T tubules may be sliding during isotonic contraction. c) The I band lengthens during isotonic contraction. d) Myofilaments slide during isometric contractions.
answer
a) Muscle tension remains relatively constant during isotonic contraction.
question
What is the most distinguishing characteristic of muscle tissue? a) the design of the fibers b) the sarcoplasmic reticulum c) the diversity of activity of muscle tissue d) the ability to transform chemical energy into mechanical energy
answer
d) the ability to transform chemical energy into mechanical energy
question
Three discrete types of muscle fibers are identified on the basis of their size, speed, and endurance. Which of the following athletic endeavors best represents the use of red fibers? a) a sprint by an Olympic runner b) a long, relaxing swim c) plaoying baseball or basketball d) mountain climbing
answer
b) a long, relaxing swim
question
Of the following muscle types, which has only one nucleus, no sacromeres, and rare gap junctions? a) visceral smooth muscle b) multiunit smooth muscle c) cardiac muscle d) skeletal muscle
answer
b) multiunit smooth muscle
question
Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overalpped, ___. a) cross bridge attachment would be optimum because of all the free binding sites on actin b) no muscle tension could be generated c) maximum for ce production would result because the muscle has a maximum range of travel d) ATP consumption would increase because the sarcomere is "trying" to contract
answer
b) no muscle tension could be generated
question
What part of the sarcolemma contains acetylcholine receptors? a) motor end plate b) end of the muscle fiber c) part adjacent to another muscle cell d) any part of the sarcolemma
answer
a) motor end plate
question
Which of the following statements is false or incorrect? a) Cardiac muscle contracts when stimulated by its own autorhythmic muscle cells. b) Under normal resting conditions, cardiac muscle tissue contracts and relaxes about 75 times per minute. c) Cardiac muscle fibers depend mostly on anaerobic cellular respiration to generate ATP. d) Cardiac muscle fibers can use lactic acid to make ATP
answer
c) Cardiac muscle fibers depend mostly on anaerobic cellular respiration to generate ATP.