chapter 9 ( B) multiple choice

B) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.

1) What is the role of tropomyosin in skeletal muscles?

A) Tropomyosin is the chemical that activates the myosin heads.

B) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.

C) Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.

D) Tropomyosin is the receptor for the motor neuron neurotransmitter.

C) smooth

2) Which muscle cells have the greatest ability to regenerate?

A) skeletal

B) cardiac

C) smooth

D) no muscle can regenerate

B) a mixture of fiber types

3) Most skeletal muscles contain ________.

A) muscle fibers of the same type

B) a mixture of fiber types

C) a predominance of slow oxidative fibers

D) a predominance of fast oxidative fibers

B) intense exercise of short duration

4) 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

C) increasing the stimulation up to the maximal stimulus

5) 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

D) motor units with larger, less excitable neurons

6) Which of the following would be recruited 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

A) Ca2+ and ATP

7) Excitation-contraction coupling requires which of the following substances?

A) Ca2+ and ATP

B) Ca2+ only

C) ATP only

D) ATP and glucose

C) load on the fiber

8) 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

C) stores oxygen in muscle cells

9) 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 potential

A) sarcoplasmic reticulum

10) What structure in skeletal muscle cells functions in calcium storage?

A) sarcoplasmic reticulum

B) mitochondria

C) intermediate filament network

D) myofibrillar network

B) the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used

11) What does excess postexercise oxygen consumption represent?

A) amount of oxygen needed for aerobic activity to accomplish the same amount of work

B) the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used

C) the amount of oxygen equal to the oxygen already used

D) the amount of oxygen taken into the body immediately after the exertion

C) latent

12) Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the neurotransmitter is released by exocytosis, diffuses across the synaptic cleft, and binds to its receptors.

A) contraction

B) relaxation

C) latent

D) refractory

D) storing energy that will be transferred to ADP to resynthesize ATP

13) Creatine phosphate functions in the muscle 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

A) produce smooth, continuous muscle contraction

14) What is the primary function of wave summation?

A) produce smooth, continuous muscle contraction

B) increase muscle tension

C) prevent muscle relaxation

D) prevent muscle fatigue

D) regulate intracellular calcium concentration

15) 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

B) the arrangement of myofilaments

16) What produces the striations of a skeletal muscle cell?

A) a difference in the thickness of the sarcolemma

B) the arrangement of myofilaments

C) the sarcoplasmic reticulum

D) the T tubules

B) actin filaments

17) During muscle contraction, myosin cross bridges attach to which active sites?

A) myosin filaments

B) actin filaments

C) Z discs

D) thick filaments

B) endomysium

18) Which of the following surrounds the individual muscle cell?

A) perimysium

B) endomysium

C) epimysium

D) fascicle

C) no ATP is available to release attached actin and myosin molecules

19) Rigor mortis occurs because ________.

A) the cells are dead

B) sodium ions leak into the muscle causing continued contractions

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

C) increases the level of lactic acid in the muscle

20) Which of the choices below does not describe how excess postexercise oxygen consumption (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

B) a sheetlike indirect attachment to a skeletal element

21) 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

C) myoglobin

22) The oxygen-binding protein found in muscle cells is ________.

A) hemoglobin

B) ATP

C) myoglobin

D) immunoglobin

D) myofibrils

23) The contractile units of skeletal muscles are ________.

A) microtubules

B) mitochondria

C) T tubules

D) myofibrils

A) a sarcomere

24) What is the functional unit of a skeletal muscle called?

A) a sarcomere

B) a myofilament

C) a myofibril

D) the sarcoplasmic reticulum

B) enhance cellular communication during muscle contraction

25) What is the functional role of the T 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

C) bind to regulatory sites on troponin to remove contraction inhibition

26) What is the role of calcium ions in muscle contraction?

A) form hydroxyapatite crystals

B) reestablish glycogen stores

C) bind to regulatory sites on troponin to remove contraction inhibition

D) increase levels of myoglobin Answer: C

D) stretching of the muscle

27) Which of the following is not a component of the standard treatment for muscle strain?

A) rest of the muscle

B) ice on the muscle

C) elevation of the limb

D) stretching of the muscle

D) aponeurosis

28) Which of the following is not a connective tissue sheath that wraps individual muscle fibers?

A) endomysium

B) perimysium

C) epimysium

D) aponeurosis

D) lactic acid

29) During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________.

A) a strong base

B) stearic acid

C) hydrochloric acid

D) lactic acid

B) refractory period

30) 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

A) changes in length and moves the "load"

31) 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

B) sarcolemma

32) The muscle cell membrane is called the ________.

A) endomysium

B) sarcolemma

C) perimysium

D) epimysium

A) motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments

33) Which of the following is the correct sequence of events for muscle contractions?

A) motor neuron action potential, neurotransmitter 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 neuron action potential, release of calcium ions from SR, sliding of myofilaments, ATP-driven power stroke

C) muscle cell action potential, neurotransmitter release, ATP-driven power stroke, calcium ion release from SR, sliding of myofilaments

D) neurotransmitter release, motor neuron action potential, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke

C) the site of calcium regulation differs

34) 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

C) They exhibit spontaneous action potentials.

35) Which of the following describes the cells of unitary smooth muscle?

A) They depend upon recruitment using the autonomic nervous system.

B) They are used for vision and hair raising.

C) They exhibit spontaneous action potentials.

D) They consist of muscle fibers that are structurally independent of each other.

D) activates epinephrine released from adrenal gland

36) Which of the following is not a role of ionic calcium in muscle contraction?

A) triggers neurotransmitter secretion

B) binds with troponin

C) removes contraction inhibitor

D) activates epinephrine released from adrenal gland

A) Certain smooth muscle cells can actually divide to increase their numbers.

37) Which of the following is true about smooth muscle?

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 muscle has well-developed T tubules at the site of invagination.

B) there are more thick filaments than thin filaments

38) Smooth muscle is characterized 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 that attach to dense bodies within the cell

A) secretion

39) Muscle tissue has all of the following properties except ________.

A) secretion

B) contractility

C) extensibility

D) excitability

A) A band

40) The giant protein titin maintains the organization of the ________ assisting in muscle stretching.

A) A band

B) I band

C) Z disc

D) M line

C) Striated muscle cells are long and cylindrical with many nuclei.

41) 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.

B) glycolysis

42) An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is ________.

A) the citric acid cycle

B) glycolysis

C) hydrolysis

D) the electron transport chain

C) a state of sustained partial contraction

43) Muscle 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 sustained partial contraction

D) the condition of athletes after intensive training

A) actin and myosin sliding past each other and partially overlapping

44) 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 lengthening in order to slide past each other

D) the Z discs sliding over the myofilaments

C) acetylcholinesterase destroying the ACh

45) 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 tropomyosin blocking the myosin once full contraction is achieved

C) acetylcholinesterase destroying the ACh

D) the action potential stops going down the overloaded T tubules

A) Muscle tension remains relatively constant during isotonic contraction.

46) 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.

D) the ability to transform chemical energy into mechanical energy

47) What is the most distinguishing characteristic of muscle tissue?

A) the design of the fibers

B) the ability to respond to nervous stimulation

C) the diversity of activity of muscle tissue

D) the ability to transform chemical energy into mechanical energy

B) a long, relaxing swim

48) 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) playing baseball or basketball

D) gym climbing

B) multiunit smooth muscle

49) Of the following muscle types, which has only one nucleus, no sarcomeres, and rare gap junctions?

A) visceral smooth muscle

B) multiunit smooth muscle

C) cardiac muscle

D) skeletal muscle

B) no muscle tension could be generated

50) Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped, ________.

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 force production would result because the muscle has a maximum range of travel

D) ATP consumption would increase because the sarcomere is "trying" to contract

A) motor end plate

51) 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

C) Cardiac muscle fibers depend mostly on anaerobic cellular respiration to generate ATP.

52) 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.