Question 1

Rigor mortis is caused by

Accepted Answer

A)  Buildup of lactic acid
B)  Lack of Ca2+
C)  Depletion of glycogen
D)  Lack of ATP
E)  Deficient acetylcholine receptorsF) A) and E)
G) None of the above

Question 2

Which of the following choices gives the correct sequence of events following the depolarization of transverse tubules in excitation-contraction coupling in cardiac muscle?

Accepted Answer

A)  Calcium release into sarcoplasm, calcium ion influx through sarcolemma, actin and myosin attach, thin myofilaments slide toward the middle of sarcomeres
B)  Actin and myosin attach, thin myofilaments slide toward the middle of sarcomeres, calcium release into sarcoplasm
C)  Calcium release into sarcoplasm, actin and myosin attach, calcium ion influx through sarcolemma, thin myofilaments slide toward the middle of sarcomeres
D)  Calcium release into sarcoplasm, actin and myosin attach, thin myofilaments slide toward the middle of sarcomeres, calcium ion influx through sarcolemma
E)  Calcium ion influx through sarcolemma, calcium release into sarcoplasm, actin and myosin attach, thin myofilaments slide toward the middle of sarcomeresF) B) and E)
G) A) and B)

Question 3

Nervous stimulation of skeletal muscle is always excitatory,whereas nervous stimulation of smooth muscle may be excitatory or inhibitory.

Accepted Answer

A) True 
 B)False

Question 4

The calcium-binding protein in smooth muscle is calmodulin.

Accepted Answer

A) True 
 B)False

Question 5

Rigor mortis occurs in a dead person because

Accepted Answer

A)  ATP, which is necessary for the detachment of cross bridges, is not being formed
B)  ATP, which is necessary for the formation of cross bridges, is not being formed
C)  ATP, which is necessary for the formation of cross bridges, continues to be formed for several hours after death
D)  Deterioration of muscle proteins prevents detachment of cross bridges
E)  None of the choices are correctF) D) and E)
G) A) and B)

Question 6

During isotonic contraction of a skeletal-muscle fiber the

Accepted Answer

A)  Sarcomeres shorten
B)  A bands shorten
C)  I bands shorten
D)  Both sarcomeres shorten and I bands shorten are correct
E)  Both A bands shorten and I bands shorten are correctF) B) and C)
G) None of the above

Question 7

Excitation-contraction coupling refers to the binding of energized myosin to actin.

Accepted Answer

A) True 
 B)False

Question 8

Which of the following is not true regarding single-unit smooth-muscle cells? They

Accepted Answer

A)  Have individual innervation of each cell
B)  Have many gap junctions between cells
C)  May have pacemaker activity
D)  Respond to stretch by contracting
E)  Have toneF) A) and E)
G) None of the above

Question 9

The energy for muscle contraction is provided by the hydrolysis of ATP.

Accepted Answer

A) True 
 B)False

Question 10

Which of the following statements regarding contraction in skeletal and smooth muscle is true?

Accepted Answer

A)  In skeletal muscle, calcium ion mediates changes in thin filaments that lead to cross-bridge activity; in smooth muscle, calcium ion mediates changes in thick filaments that lead to cross-bridge activity
B)  In skeletal muscle, calcium ion binds to a regulatory protein on thin filaments; in smooth muscle, calcium ion binds to a regulatory protein on thick filaments
C)  In skeletal muscle, calcium ion binds to troponin; in smooth muscle, calcium ion binds to calmodulin
D)  Both in skeletal muscle, calcium ion mediates changes in thin filaments that lead to cross-bridge activity; in smooth muscle, calcium ion mediates changes in thick filaments that lead to cross-bridge activity and in skeletal muscle, calcium ion binds to troponin; in smooth muscle, calcium ion binds to calmodulin are true
E)  All of the choices are trueF) A) and D)
G) All of the above

Question 11

A large diameter is typical of which type of skeletal-muscle fibers?

Accepted Answer

A)  Type I
B)  Type IIC) A) and B)
D) undefined

Question 12

Olympic speed (ice) skaters have large,muscular legs that are unusual in that the left leg is generally even larger in diameter than the right.This is an example of

Accepted Answer

A)  Disuse atrophy of the right leg
B)  Hypertrophy of fast-glycolytic muscle fibers as a result of exercise
C)  An increase in the number of fast muscle fibers as a result of exercise
D)  Both disuse atrophy of the right leg and hypertrophy of fast-glycolytic muscle fibers as a result of exercise
E)  Both hypertrophy of fast-glycolytic muscle fibers as a result of exercise and an increase in the number of fast muscle fibers as a result of exerciseF) B) and E)
G) A) and E)

Question 13

The removal of calcium ions from the cytosol of skeletal muscle causes

Accepted Answer

A)  The myosin binding sites on actin to be uncovered by tropomyosin
B)  Tropomyosin to change conformation and thereby move troponin molecules over cross-bridge binding sites
C)  Troponin to change conformation and thereby expose cross-bridge binding sites
D)  The myosin binding sites on actin to be covered by tropomyosin
E)  None of the choices are correctF) None of the above
G) B) and D)

Question 14

In cardiac muscle contractile cells the release of calcium through L-type calcium channels depolarizes the sarcoplasmic reticulum and inhibits the release of any additional calcium necessary for excitation-contraction coupling.

Accepted Answer

A) True 
 B)False

Question 15

Myasthenia gravis

Accepted Answer

A)  Is an autoimmune disease
B)  Occurs when the motor neuron terminals cannot secrete enough acetylcholine to stimulate the motor end plate adequately
C)  Can be treated with a drug that temporarily inhibits acetylcholinesterase
D)  Both is an autoimmune disease and occurs when the motor neuron terminals cannot secrete enough acetylcholine to stimulate the motor end plate adequately are correct
E)  Both is an autoimmune disease and can be treated with a drug that temporarily inhibits acetylcholinesterase are correctF) A) and E)
G) None of the above

Question 16

Binding of ________ to myosin permits cross-bridge _____________ between actin and myosin.

Accepted Answer

A)  ATP; attachment
B)  ATP; detachment
C)  Calcium; attachment
D)  Calcium; detachment
E)  Actin; detachmentF) B) and E)
G) D) and E)

Question 17

All isotonic contractions begin and end as isometric contractions.

Accepted Answer

A) True 
 B)False

Question 18

An action potential in the motor end plate rapidly spreads to the central portions of a muscle cell by means of the

Accepted Answer

A)  Z lines
B)  Sarcoplasmic reticulum
C)  H zone
D)  Transverse tubules
E)  Pores in the plasma membraneF) D) and E)
G) A) and D)

Question 19

Which of the following is not a determinant of whole-muscle tension?

Accepted Answer

A)  Number of muscle fibers contracting
B)  Tension produced by each contracting fiber
C)  Extent of motor unit recruitment
D)  Frequency of motor neuron stimulation
E)  Proportion of the muscle fibers in each motor unit that are contracting at any given timeF) C) and D)
G) B) and C)

Question 20

During isometric contraction of a skeletal-muscle fiber,tension increases but the fiber length stays the same.

Accepted Answer

A) True 
 B)False

Exam 9: Muscle

Rigor mortis is caused by

Correct AnswerverifiedShow Answer

Which of the following is not a determinant of whole-muscle tension?

Correct AnswerverifiedShow Answer

Binding of ________ to myosin permits cross-bridge _____________ between actin and myosin.

Correct AnswerverifiedShow Answer

Rigor mortis occurs in a dead person because

Correct AnswerverifiedShow Answer

An action potential in the motor end plate rapidly spreads to the central portions of a muscle cell by means of the

Correct AnswerverifiedShow Answer

Which of the following is not true regarding single-unit smooth-muscle cells? They

Correct AnswerverifiedShow Answer

The removal of calcium ions from the cytosol of skeletal muscle causes

Correct AnswerverifiedShow Answer

During isotonic contraction of a skeletal-muscle fiber the

Correct AnswerverifiedShow Answer

A large diameter is typical of which type of skeletal-muscle fibers?

Correct AnswerverifiedShow Answer

Which of the following statements regarding contraction in skeletal and smooth muscle is true?

Correct AnswerverifiedShow Answer

All isotonic contractions begin and end as isometric contractions.

Correct AnswerverifiedShow Answer

The calcium-binding protein in smooth muscle is calmodulin.

Correct AnswerverifiedShow Answer

The energy for muscle contraction is provided by the hydrolysis of ATP.

Correct AnswerverifiedShow Answer

Myasthenia gravis

Correct AnswerverifiedShow Answer

Which of the following choices gives the correct sequence of events following the depolarization of transverse tubules in excitation-contraction coupling in cardiac muscle?

Correct AnswerverifiedShow Answer

Nervous stimulation of skeletal muscle is always excitatory,whereas nervous stimulation of smooth muscle may be excitatory or inhibitory.

Correct AnswerverifiedShow Answer

Olympic speed (ice) skaters have large,muscular legs that are unusual in that the left leg is generally even larger in diameter than the right.This is an example of

Correct AnswerverifiedShow Answer

Excitation-contraction coupling refers to the binding of energized myosin to actin.

Correct AnswerverifiedShow Answer

During isometric contraction of a skeletal-muscle fiber,tension increases but the fiber length stays the same.

Correct AnswerverifiedShow Answer

In cardiac muscle contractile cells the release of calcium through L-type calcium channels depolarizes the sarcoplasmic reticulum and inhibits the release of any additional calcium necessary for excitation-contraction coupling.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Binding of to myosin permits cross-bridge _____ between actin and myosin.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified