PhysioEx 9.1: Laboratory Simulations In Physiology, 1st Edition Test Bank

Exam Name___________________________________ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which starting length of the muscle provided the maximum total force? A) the longest starting length B) the shortest starting length C) an intermediate starting length D) The length of the muscle did not affect the amount of total force produced. Answer: C Explanation: A) B) C) D) 2) Which of the following terms are NOT used interchangeably? A) in vivo — in the body B) muscle cell — muscle fiber C) motor unit — motor neuron D) muscle tension — muscle force Answer: C Explanation: 3) A) B) C) D) 4) As the weight increased, the distance the weight was lifted _______. A) decreased until the weight was not moved at all B) increased C) decreased D) did not change Answer: A Explanation: 2) A) B) C) D) 3) Which of the following is proportional to the amount of tension produced by a skeletal muscle? A) the length of the latent period B) the length of the relaxation phase C) the number of motor units activated D) the threshold voltage Answer: C Explanation: 1) A) B) C) D) 1 4) 5) Which of the following occurs if the load attempted is equal to or greater than the force generated by a muscle? A) Isometric muscle contraction occurs. B) The muscle shortens. C) The muscle lengthens. D) Isotonic muscle contraction occurs. Answer: A Explanation: A) B) C) D) 6) Which of the following produced an increase in stimulus intensity? A) clicking the mouse in rapid succession and allowing the muscle to completely relax in between contractions B) clicking the mouse in rapid succession C) allowing the muscle to completely relax in between contractions D) increasing the voltage applied Answer: D Explanation: 7) A) B) C) D) E) 8) Treppe is the phenomenon that results in _______. A) a progressive increase in the force generated with repetitive stimulation B) an increase in the stimulation frequency C) maximal force production by a skeletal muscle D) motor unit recruitment Answer: A Explanation: 6) A) B) C) D) 7) Which of the following is true of the maximum stimulus frequency? A) Muscle has reached maximal tetanic tension. B) Muscle force will decrease. C) No greater muscle force can be generated and muscle force will decrease. D) No greater muscle force can be generated. E) No greater muscle force can be generated and the muscle has reached maximal tetanic tension. Answer: E Explanation: 5) A) B) C) D) 2 8) 9) The resting length of the muscle _______. A) occurs when peak tension develops. B) describes the length of the muscle during contraction. C) occurs when the muscle is relaxed. D) describes the muscle during stimulation. Answer: C Explanation: A) B) C) D) 10) Which of the following occurs during the latent period of muscle contraction? A) An action potential is generated. B) Acetylcholine is released at the axon terminal and an action potential is generated. C) Calcium is released from the sarcoplasmic reticulum. D) Acetylcholine is released at the axon terminal. Answer: C Explanation: 11) A) B) C) D) E) 12) Increasing the applied voltage in the simulation corresponds to which in vivo event? A) motor neuron recruitment B) motor unit recruitment C) muscle fiber recruitment D) muscle twitch recruitment Answer: B Explanation: 10) A) B) C) D) 11) For a weight to be lifted, which of the following must occur? A) isotonic muscle contraction with a force less than the load B) isotonic muscle contraction with a force greater than the load C) isometric muscle contraction with a force greater than the load D) either isometric or isotonic muscle contraction with a force greater than the load E) either isotonic muscle contraction with a force greater than the load or a force less than the load Answer: B Explanation: 9) A) B) C) D) 3 12) 13) Which of the following is generated when cross-bridges form between actin and myosin? A) active force and passive force B) active force and ATP C) active force D) ATP E) passive force Answer: C Explanation: A) B) C) D) E) 14) Which of the following occurs during the latent period of isotonic concentric contraction? A) Muscle tension is not produced, and the weight will not move. B) Muscle tension is produced, and the weight will move. C) Muscle tension is produced, and the weight will not move. D) Muscle tension is not produced, and the weight will move. Answer: C Explanation: 15) A) B) C) D) 16) When the frequency of stimulation of a muscle is great enough, _______. A) full relaxation of the muscle occurs and wave summation results B) full relaxation of the muscle occurs C) muscle twitches overlap D) wave summation results and muscle twitches overlap E) wave summation results Answer: D Explanation: 14) A) B) C) D) 15) Which of the following is NOT a phase of a muscle twitch? A) relaxation phase B) contraction phase C) latent period D) shortening phase Answer: D Explanation: 13) A) B) C) D) E) 4 16) 17) As the stimulus voltage increased, the resulting muscle tension _______. A) remained the same B) decreased proportionally C) increased to a point until it reached a plateau D) increased proportionally Answer: C Explanation: A) B) C) D) 18) When acetylcholine binds to its receptors, it results in __________. A) the end plate potential, a graded depolarization, and a change in ion permeability B) a change in ion permeability C) a graded depolarization D) the end plate potential Answer: A Explanation: 20) A) B) C) D) 21) NO force is generated during which of the following? A) a muscle twitch B) the relaxation phase C) the latent period D) the contraction phase Answer: C Explanation: 19) A) B) C) D) 20) To transition from unfused tetanus to fused tetanus, _______. A) stimulus frequency increased B) the muscle fibers were allowed to relax C) stimulus frequency decreased D) wave summation was not allowed Answer: A Explanation: 18) A) B) C) D) 19) Which of the following does NOT lead to muscle fatigue? A) high-intensity exercise of a long duration B) maximal tetanic tension C) repetitive stimulation of a muscle D) prolonged muscle contraction Answer: B Explanation: 17) A) B) C) D) 5 21) 22) At which muscle length was the passive force the greatest? A) 90 mm B) 100 mm C) 80 mm Answer: B Explanation: D) 70 mm A) B) C) D) 23) The shortest duration of muscle contraction occurs with _______. A) the lightest load B) the intermediate load C) the heaviest load D) The duration of muscle contraction doesn’t vary with the load lifted. Answer: C Explanation: 25) A) B) C) D) 26) Which of the following is matched correctly? A) incomplete tetanus — fatigue C) incomplete tetanus — fused tetanus Answer: D Explanation: 24) A) B) C) D) 25) Which of the following describes the relationship between stimulus frequency and muscle tension? A) When stimulus frequency increases, muscle tension decreases. B) When stimulus frequency increases, muscle tension increases to a maximum value. C) When stimulus frequency decreases, muscle tension increases indefinitely. D) When stimulus frequency increases, muscle tension increases indefinitely. Answer: B Explanation: 23) A) B) C) D) 24) The speed of muscle contraction is called the _______. A) contraction velocity B) twitch velocity C) isometric velocity D) shortening velocity Answer: D Explanation: 22) B) complete tetanus — unfused tetanus D) complete tetanus — fused tetanus A) B) C) D) 6 26) 27) Which of the following molecules is NOT thought to accumulate during muscle fatigue? A) lactic acid B) ADP C) inorganic phosphate D) ATP Answer: D Explanation: A) B) C) D) 28) Which of the following does NOT describe treppe? A) An increase in stimulus intensity is required to see the effect. B) A period of relaxation can be seen on the muscle twitch tracing. C) An incremental increase in force occurs. D) It is also referred to as the “staircase” effect. Answer: A Explanation: 29) A) B) C) D) 30) Which of the following can trigger a muscle twitch? A) release of acetylcholine and electrical stimulation B) electrical stimulation C) release of acetylcholine and release of calcium from the sarcolemma D) release of acetylcholine E) release of calcium from the sarcolemma Answer: A Explanation: 28) A) B) C) D) 29) Why does wave summation occur? A) Muscle twitches are not yet overlapping. B) A large amount of time elapses between stimulations. C) Muscle fibers have been allowed to fully relax. D) Muscle fibers are partially contracted when the next stimulus arrives. Answer: D Explanation: 27) A) B) C) D) E) 7 30) 31) In this activity, why did the muscle force decrease over time? A) The stimulation frequency was increased. B) The stimulation frequency was decreased. C) Intracellular calcium built up. D) Muscle fatigue developed. Answer: D Explanation: A) B) C) D) 32) When the load to be lifted increases in weight, the latent period _______. A) decreases and disappears B) decreases C) remains unchanged D) increases Answer: D Explanation: B) threshold voltage applied D) fused tetanus only 33) A) B) C) D) 34) In the lab, a researcher finds that the threshold stimulus to induce an action potential in a muscle fiber’s sarcolemma was 3.0 volts. Which of the following would result in muscle tension? A) 4.0 volts B) 3.0 volts C) 3.0 volts and 4.0 volts D) 1.0 volt E) 2.0 volts Answer: C Explanation: 32) A) B) C) D) 33) Muscle twitches overlap with _______. A) both fused and unfused tetanus C) unfused tetanus only Answer: A Explanation: 31) A) B) C) D) E) 8 34) 35) Why does the active force of skeletal muscle change with the muscle’s resting length? A) The amount of resistance varies. B) The number of cross-bridges between actin and myosin varies. C) The amount of available calcium varies. D) The amount of available ATP varies. Answer: B Explanation: A) B) C) D) 36) During muscle fatigue, the ____________ decreases. A) rest period C) stimulus frequency Answer: D Explanation: B) number of muscle fibers D) force of contraction 38) A) B) C) D) 39) What is the minimum voltage needed to generate muscle contraction? A) threshold voltage B) stimulus voltage C) contraction voltage D) recruitment voltage Answer: A Explanation: 37) A) B) C) D) 38) What might be occurring on a molecular level during the rest periods? A) Intracellular ADP and inorganic phosphate are decreasing. B) Intracellular lactic acid is increasing. C) Muscle fatigue is increasing. D) Intracellular calcium is decreasing. Answer: A Explanation: 36) A) B) C) D) 37) Which of the following describes the relationship between length and tension? A) The active force can increase or decrease, depending on the starting resting length of the muscle. B) As the muscle’s resting length increases, the active force will decrease. C) As the muscle’s resting length decreases, the active force will decrease. D) As the muscle’s resting length increases, the active force will increase. Answer: A Explanation: 35) A) B) C) D) 9 39) 40) Which of the following describes how increasing the duration of the rest period affected muscle tension? A) Decreasing the duration of the rest period increased muscle tension. B) Decreasing the duration of the rest period decreased muscle tension. C) Increasing the duration of the rest period increased muscle tension. D) Increasing the duration of the rest period decreased muscle tension. Answer: C Explanation: A) B) C) D) 41) The velocity of shortening _______. A) decreased as the weight increased B) increased as the weight increased C) decreased as the weight increased and increased as the weight decreased D) increased as the weight decreased Answer: C Explanation: 42) A) B) C) D) 43) Which of the following would result in fused or unfused tetanus? A) increasing the stimulus frequency B) decreasing the stimulus frequency or increasing the stimulus frequency C) decreasing the stimulus frequency D) threshold stimulus and single stimuli Answer: A Explanation: 41) A) B) C) D) 42) Which of the following is occurring during the contraction phase? A) Acetylcholine binds to the sarcolemma. B) Calcium is released from the sarcoplasmic reticulum. C) Cross-bridge cycling is taking place. D) The sarcomeres are increasing in length. Answer: C Explanation: 40) A) B) C) D) 10 43) 44) A motor unit is defined as _______. A) the axon terminals of a single motor neuron and all of the muscle fibers that it stimulates B) a nerve and a muscle C) a single muscle fiber and all its axon terminals D) a single neuron and a single muscle fiber Answer: A Explanation: A) B) C) D) 45) Which of the following occurs during isotonic concentric contraction? A) The length of the muscle decreases with contraction. B) The length of the muscle increases with contraction. C) The length of the muscle increases and decreases with contraction. D) The length of the muscle stays the same. Answer: A Explanation: 46) 47) A) B) C) D) 48) Which of the following does NOT describe tetanus? A) The muscle relaxes fully between contractions. B) It can be unfused. C) It can be fused. D) The maximum force produced has reached a plateau. Answer: A Explanation: D) 130 stimuli/sec A) B) C) D) 47) When wave summation occurs, _______. A) the muscle force generated increases B) the muscle fiber has received a single stimulus event C) individual muscle twitches are separated D) the muscle force generated decreases Answer: A Explanation: 45) A) B) C) D) 46) At what stimulus frequency was maximal tetanic tension developed? A) 50 stimuli/sec B) 146 stimuli/sec C) 140 stimuli/sec Answer: B Explanation: 44) A) B) C) D) 11 48) 49) Where does the acetylcholine released for muscle contraction bind? A) receptors in troponin B) receptors in the axon terminal C) receptors in the sarcoplasmic reticulum D) receptors in the motor end plate Answer: D Explanation: A) B) C) D) 50) Which of the following describes the relaxation phase? A) The sarcomeres are increasing in length, and the force generated decreases. B) The sarcomeres are decreasing in length, and the force generated decreases. C) The sarcomeres are decreasing in length, and the force generated increases. D) The sarcomeres are increasing in length, and the force generated increases. Answer: B Explanation: 51) A) B) C) D) E) 52) Which of the following describes how you were able to achieve an active force of 5.2 g? A) by applying multiple stimuli at 8.5 volts B) by applying multiple stimuli at 10 volts C) by applying multiple stimuli at 12 volts D) by applying a single stimulus at 8.5 volts Answer: B Explanation: 50) A) B) C) D) 51) The graph of the length-tension relationship illustrates _______. A) the optimal sarcomere length for muscle contraction and the amount of overlap between the thick and thin filaments in the resting muscle B) the relationship between muscle diameter and tension and the optimal sarcomere length for muscle contraction C) the relationship between muscle diameter and tension D) the optimal sarcomere length for muscle contraction E) the amount of overlap between the thick and thin filaments in the resting muscle Answer: A Explanation: 49) A) B) C) D) 12 52) 53) As the stimulus voltage was increased in this activity, which of the following occurred? A) The muscle force generated decreased. B) The latent period increased in length. C) The latent period decreased in length. D) The muscle force generated increased. Answer: D Explanation: A) B) C) D) 54) Which of the following produced an increase in stimulus frequency? A) increasing the voltage applied B) clicking the mouse in rapid succession and allowing the muscle to completely relax in between contractions C) clicking the mouse in rapid succession D) allowing the muscle to completely relax between contractions Answer: C Explanation: 53) A) B) C) D) 13 54) Answer Key Testname: EX2 1) C 2) C 3) C 4) A 5) A 6) D 7) E 8) A 9) C 10) C 11) B 12) B 13) C 14) C 15) D 16) D 17) C 18) A 19) B 20) A 21) C 22) B 23) C 24) D 25) B 26) D 27) D 28) A 29) D 30) A 31) D 32) D 33) A 34) C 35) B 36) D 37) A 38) A 39) A 40) C 41) C 42) C 43) A 44) A 45) A 46) B 47) A 48) A 49) D 50) B 14 Answer Key Testname: EX2 51) A 52) B 53) D 54) C 15