Deck 8: Histology and Physiology of Muscles

Question 1

Which of the following is a function of smooth muscle?

A) Communication
B) Production of body heat
C) Constriction of organs and vessels
D) Respiration

Answer 1

Constriction of organs and vessels

Question 2

Which type of muscle is needed for propelling blood throughout the body?

A) Cardiac
B) Smooth
C) Skeletal

Answer 2

Cardiac

Question 3

The ability of muscle to shorten forcefully is

A) Contractility
B) Excitability
C) Extensibility
D) Elasticity

Answer 3

Contractility

Question 4

The ability of muscle to respond to a stimulus is

A) Contractility
B) Excitability
C) Extensibility
D) Elasticity

Question 5

The ability of muscle to contract when stretched beyond its normal resting length is

A) Contractility
B) Excitability
C) Extensibility
D) Elasticity

Question 6

The ability of muscle to recoil to its resting length after being stretched is

A) Contractility
B) Excitability
C) Extensibility
D) Elasticity

Question 7

Which of the following is NOT true of skeletal muscle?

A) Long, cylindrical fibers
B) Multiple nuclei
C) Totally under involuntary control
D) Has striations

Question 8

Which of the following is true of smooth muscle?

A) Visceral cells connected by intercalated disks
B) Non-striated, spindle-shaped cells
C) Under voluntary control
D) Found attached to bones

Question 9

What type of connective tissue separates and compartmentalizes muscles?

A) Epimysium
B) Perimysium
C) Muscular fascia
D) Endomysium

Question 10

What type of connective tissue creates the muscle fasciculus?

A) Epimysium
B) Perimysium
C) Muscular fascia
D) Endomysium

Question 11

What type of connective tissue surrounds individual muscle fibers?

A) Epimysium
B) Perimysium
C) Muscular fascia
D) Endomysium

Question 12

What type of connective tissue surrounds individual muscles?

A) Epimysium
B) Perimysium
C) Muscular fascia
D) Endomysium

Question 13

What is the plasma membrane of a muscle fiber called?

A) Sarcoplasm
B) Sarcomere
C) Sarcolemma
D) Endomysium

Question 14

Myofibrils are formed from ____________ that are joined end to end.

A) Actin myofilaments
B) Sarcomeres
C) Myosin myofilaments
D) Sarcolemmas

Question 15

Which molecule covers the active site on the G actin?

A) Tropomyosin
B) Troponin
C) Titin
D) M line

Question 16

Which molecule has a binding site for calcium?

A) Tropomyosin
B) Troponin
C) Titin
D) M line

Question 17

Which of the following is NOT a part of the myosin molecule?

A) Rod
B) M line
C) Hinge region
D) Head

Question 18

Which molecule is attached to the Z disk?

A) Troponin
B) Myosin
C) Actin
D) Tropomyosin

Question 19

The I band is made up of

A) Myosin and titin
B) A Z disk and actin
C) The M line and Z disk
D) Actin and myosin

Question 20

The A band is made up of

A) Myosin and titin
B) A Z disk and actin
C) The M line and Z disk
D) Actin and myosin

Question 21

The H zone is where

A) There is only actin
B) There is only myosin
C) There is only the Z disk
D) There is only titin

Question 22

Which molecule is responsible for allowing the sarcomere to stretch and recoil?

A) Titin
B) Troponin
C) Actin
D) Myosin

Question 23

The structural and functional unit of skeletal muscle is the

A) Sarcolemma
B) Actin myofilament
C) Sarcomere
D) Myosin myofilament

Question 24

What shortens during the sliding filament model of muscle contraction?

A) H zone, A band and sarcomere
B) A band, I band and sarcomere
C) Sarcomere, H zone and I band
D) A band, I band and H zone

Question 25

Which statement is true of a resting membrane potential?

A) The plasma membrane is negative on the outside with more sodium ions outside
B) The plasma membrane is negative on the outside with more potassium ions outside
C) The plasma membrane is positive on the outside with more sodium ions outside
D) The plasma membrane is positive on the outside with more potassium ions outside

Question 26

What type of gated ion channel responds to a molecule binding to a receptor on the ion channel?

A) Ligand-gated ion channel
B) Steroid-gated ion channel
C) Voltage-gated ion channel
D) Messenger-gated ion channel

Question 27

The binding of acetylcholine to a ligand-gated channel will allow ____ to enter the muscle fiber.

A) Calcium ions
B) Potassium ions
C) Sodium ions
D) All of the choices are correct

Question 28

What kind of gated ion channel responds to small changes in voltages across the plasma membrane?

A) Ligand-gated ion channel
B) Steroid-gated ion channel
C) Voltage-gated ion channel
D) Messenger-gated ion channel

Question 29

Which of the following is NOT an important voltage-gated ion channel on a muscle or nerve plasma membrane?

A) Magnesium
B) Sodium
C) Calcium
D) Potassium

Question 30

What occurs during the process of depolarization?

A) Potassium gates open out of the cell making the outside more positive
B) Sodium gates open into the cell making the inside more negative
C) Calcium gates open into the cell making the inside more positive
D) Sodium gates open into the cell making the inside more positive

Question 31

What occurs during the process of repolarization?

A) Potassium gates open out of the cell making the outside more positive
B) Sodium gates open into the cell making the inside more negative
C) Calcium gates open into the cell making the inside more positive
D) Sodium gates open into the cell making the inside more positive

Question 32

Which of the following is NOT part of a neuromuscular junction?

A) Motor end-plate
B) Presynaptic terminal
C) Sarcoplasmic reticulum
D) Synaptic cleft

Question 33

What ion is necessary for the release of acetylcholine from the synaptic vesicles?

A) Sodium
B) Calcium
C) Chloride
D) Potassium

Question 34

By what process does acetylcholine move to the postsynaptic membrane?

A) Active transport
B) Endocytosis
C) Diffusion
D) Osmosis

Question 35

What is the role of acetylcholinesterase?

A) To bind acetylcholine to its ligand-gated Na⁺ channel receptor
B) To remove and breakdown acetylcholine from the channel receptor
C) To create a new action potential on the sarcolemma
D) All of the choices are roles of acetylcholinesterase

Question 36

How ischoline returned to the synaptic vesicles?

A) Diffusion with acetic acid
B) Antiport with acetic acid
C) Symport with sodium
D) Endocytosis

Question 37

The mechanism by which an action potential in the sarcolemma causes a muscle contraction is called

A) Excitation-contraction coupling
B) Sliding-filament model
C) Synaptic excitation
D) Cross-bridge cycling

Question 38

Extensions of the sarcolemma into the interior of the muscle fiber are called

A) Cisternae
B) Sarcoplasmic reticulae
C) T tubules
D) Triads

Question 39

What is the relationship between T tubules and terminal cisternae of the sarcoplasmic reticulum called?

A) Neuromuscular junction
B) Triad
C) Cross-bridge
D) Voltage-gated channel

Question 40

What is the direct cause of the release of calcium ions from the sarcoplasmic reticulum?

A) Acetylcholine binding to the receptor on the Na⁺ gated channel
B) Calcium being released into the presynaptic terminal
C) The action potential traveling into the T tubules
D) Potassium flowing out of the postsynaptic membrane

Question 41

What is ATP directly used for in cross-bridge movement of myosin?

A) Attachment of the myosin head to the active site of actin
B) The power stroke of the myosin head
C) The release of the myosin head from the actin
D) All of the choices are correct

Question 42

What is released from the myosin head when the cross-bridge with actin is formed?

A) Phosphate
B) ADP
C) ATP
D) Calcium

Question 43

What is released from the myosin head after the power stroke occurs?

A) Phosphate
B) ADP
C) ATP
D) Calcium

Question 44

Which of the following is NOT involved in the process of muscle relaxation?

A) The sarcoplasmic reticulum actively reclaims calcium ions using ATP
B) The troponin-tropomyosin complex blocks the active site on actin again
C) ATP is used for cross-bridge release
D) All of the above occurs during relaxation

Question 45

Which of the following is NOT a phase of a muscle twitch?

A) Interphase
B) Contraction phase
C) Lag phase
D) Relaxation phase

Question 46

Which of the following is NOT an event that occurs during the lag phase of a muscle twitch?

A) Acetylcholine diffuses across the synaptic cleft
B) The action potential travels down the T tubules
C) Cross-bridges between actin and myosin are formed
D) Calcium ions bind to troponin

Question 47

What type of stimulus will cause all the motor units of a muscle to respond?

A) Subthreshold
B) Threshold
C) Submaximal
D) Maximal

Question 48

The overall force of a contract can increase due to

A) Multiple motor unit summation
B) Multiple wave summation
C) A supramaximal stimulus
D) A maximal stimulus

Question 49

What is it called when action potentials come so fast that the muscle fiber does not relax between them?

A) Treppe
B) Incomplete tetanus
C) Tetanus
D) Recruitment

Question 50

A gradual increase in muscle tension in a muscle that has been resting is called

A) Treppe
B) Incomplete tetanus
C) Tetanus
D) Multiple-wave summation

Question 51

Tightening your leg muscles while sitting in an airplane would be an example of a(an) ______________
Contraction.

A) Isometric
B) Isotonic
C) Concentric
D) Eccentric

Question 52

Flexing your fingers to grasp a screwdriver would be an example of a(an) ______ contraction.

A) Isometric
B) Isotonic
C) Concentric
D) Eccentric

Question 53

Doing an arm curl (flexing the elbow) while holding a three-pound weight would be an example of a(an) ___________ contraction.

A) Isometric
B) Isotonic
C) Concentric
D) Eccentric

Question 54

Extending your forearm (lowering the forearm after flexing it) while holding a three-pound weight would be an example of a(an) _______ contraction.

A) Isometric
B) Isotonic
C) Concentric
D) Eccentric

Question 55

The constant tension in muscles over a long period of time that allows you to hold up your head is called

A) Treppe
B) Incomplete tetanus
C) Muscle tone
D) An eccentric contraction

Question 56

What occurs in psychologic fatigue?

A) Muscles cannot relax due to inadequate ATP
B) Muscles can contract but an individual thinks they cannot
C) Cross-bridging cannot occur due to lack of ATP
D) Not enough calcium is present to allow cross-bridging

Question 57

What occurs in physiologic contracture?

A) Muscles cannot relax due to inadequate ATP
B) Muscles can contract but an individual thinks they cannot
C) Cross-bridging cannot occur due to lack of ATP
D) Not enough calcium is present to allow cross-bridging

Question 58

Which of the following is NOT a source of ATP for muscle contraction?

A) Aerobic respiration
B) Anaerobic respiration
C) Creatine phosphate
D) Sarcoplasmic reticulum

Question 59

Creatine phosphate is used to

A) Regenerate ATP from ADP
B) Breakdown glucose to make ATP
C) Provide oxygen to make ATP
D) Change lactic acid into ATP

Question 60

When is anaerobic respiration used by muscle cells?

A) For sustained exercise
B) During rest
C) For short periods of intense exercise
D) For moderate exercise

Question 61

How many ATPs are produced from one glucose during anaerobic respiration?

A) 2
B) 4
C) 26
D) 38

Question 62

For how long does creatine phosphate provide ATP for contraction?

A) Up to 3 minutes
B) Up to 10 seconds
C) Up to 1 hour
D) Several hours

Question 63

For how long does anaerobic respiration provide ATP for contraction?

A) Up to 3 minutes
B) Up to 10 seconds
C) Up to 1 hour
D) Several hours

Question 64

What is the main source of ATP production in skeletal muscle for sustained exercise and during rest?

A) Creatine phosphate
B) Glucose
C) Glycogen
D) Fatty acids

Question 65

How many ATPs are produced from aerobic respiration of one glucose molecule?

A) 2
B) 4
C) 26
D) 38

Question 66

What waste product is produced during anaerobic respiration?

A) Pyruvic acid
B) Carbon dioxide
C) Lactic acid
D) Creatine phosphate

Question 67

The lack of oxygen relative to increased muscular activity at the beginning of exercise is called

A) Oxygen debt
B) Recovery oxygen consumption
C) Psychologic fatigue
D) Muscular fatigue

Question 68

The elevated use of oxygen once exercise has stopped is called

A) Oxygen debt
B) Recovery oxygen consumption
C) Psychologic fatigue
D) Muscular fatigue

Question 69

How does the body respond to an increase in body temperature due to exercise?

A) Shivering
B) Decreased muscle contractions
C) Dilation of skin blood vessels and sweating
D) Slower respiration

Question 70

What determines the speed of contraction of a skeletal muscle fiber?

A) The amount of ATP present
B) The type of ATPase breaking down ATP
C) The type of myosin head
D) The amount of glycogen present

Question 71

Which of the following is NOT true of slow-twitch oxidative fibers?

A) Highly fatigue-resistant
B) Have many mitochondria
C) Have high myoglobin content
D) Have high glycogen stores

Question 72

Which of the following is NOT true of fast-twitch glycolytic fibers?

A) Fast ATPase activity
B) Low anaerobic activity
C) Few mitochondria and blood vessels
D) Low myoglobin content

Question 73

The most fatigable fibers are

A) FOG fibers
B) FG fibers
C) SO fibers
D) None of the choices are correct

Question 74

What type of activity are SO fibers adapted to?

A) Posture and prolonged exercise
B) Sprinting
C) Moderate-intensity endurance exercise
D) Arm curls with weights

Question 75

What causes muscle hypertrophy?

A) An increase in the number of muscle fibers
B) Fibers increase the number of myofibril and sarcomere
C) Skeletal muscle cell nuclei divide
D) All of the choices are correct

Question 76

What factors increase the strength of trained muscles?

A) More motor units are recruited
B) Less restricted by fat
C) Greater uptake of nutrients and ATP production
D) All of the choices are correct

Question 77

A person who had their leg in a cast for two months would experience

A) Muscle hypertrophy
B) Denervation atrophy
C) Disuse atrophy
D) Muscular dystrophy

Question 78

Which of the following is NOT an age-related change of skeletal muscle?

A) Decreased recovery time from exercise
B) Reduction of muscle mass
C) Reduced stamina
D) Loss of fast-twitch muscle fibers

Question 79

Which of the following is NOT a characteristic of visceral smooth muscle?

A) Found in the walls of hollow organs
B) Occur in sheets
C) Can function as independent cells
D) Have many gap junctions

Question 80

Where would multiunit smooth muscle NOT be found?

A) Ureter
B) Arrector pili muscles in skin
C) Iris of the eye
D) Spleen