Deck 9: Muscular System: Histology and Physiology

Question 1

Which type of muscle tissue is multinucleated?

A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
D) Both skeletal and cardiac muscle are correct.
E) Both cardiac and smooth muscle are correct.

Answer 1

A

Question 2

Which type of muscle tissue causes contraction of the heart?

A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle

Answer 2

C

Question 3

Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the

A) number of muscle fibers.
B) size of muscle fibers.
C) number of striations.
D) number of nuclei within the muscle fibers.
E) number of muscle cells.

Answer 3

B

Question 4

Smooth muscle and cardiac muscle are similar in that they both

A) are under involuntary control.
B) are striated.
C) are widely distributed in the body.
D) have multiple nuclei.
E) are under voluntary control.

Question 5

Which of the following statements about muscle tissue is true?

A) Skeletal muscle is capable of spontaneous contraction.
B) Smooth muscle is found in the walls of hollow organs.
C) Cardiac muscle cells have multiple nuclei.
D) Smooth muscle cells are long and cylindrical.
E) There is a small amount of smooth muscle in the heart.

Question 6

Which type of muscle tissue has neuromuscular junctions?

A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle

Question 7

Which type of muscle tissue would cause flexion and extension of the arm?

A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle

Question 8

Which of the following actions is caused by contraction of skeletal muscle?

A) Contraction of the heart
B) Moving your feet in walking
C) Movement of food through the digestive tract
D) Emptying of the urinary bladder
E) Vasoconstriction

Question 9

Which type of muscle tissue has cells that branch?

A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
D) Both skeletal and cardiac muscle are correct.
E) Both cardiac and smooth muscle are correct.

Question 10

Identify the statement concerning skeletal muscle that is true.

A) It comprises about 20% of the body's weight.
B) It propels urine through the urinary tract.
C) Its function is largely under involuntary control.
D) It is a kind of connective tissue.
E) It is responsible for locomotion.

Question 11

The capacity of a muscle cell to shorten forcefully is known as

A) contractility.
B) excitability.
C) extensibility.
D) elasticity.
E) flexibility.

Question 12

Which type of muscle tissue has spindle-shaped cells?

A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
D) Both skeletal and cardiac muscle are correct.
E) Both cardiac and smooth muscle are correct.

Question 13

Which of the following is NOT a function of skeletal muscle?

A) Body movement
B) Maintenance of posture
C) Respiration
D) Constriction of organs
E) Production of heat

Question 14

Muscles exhibit the property of excitability. This means that the muscle

A) shortens its length.
B) recoils to its original resting length.
C) stretches beyond its normal length.
D) responds to stimulation by the nervous system.
E) excites itself.

Question 15

Which type of muscle tissue causes vasoconstriction?

A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle

Question 16

Skeletal muscle fibers

A) possess striations.
B) can contract but are not extensible or excitable.
C) do not require nerve innervation to contract.
D) increase dramatically in number after birth.
E) are found in the walls of the stomach.

Question 17

Identify the statement concerning general functional characteristics of muscle that is true.

A) Muscle tissue shortens forcefully but lengthens passively.
B) Muscle tissue shortens passively but lengthens forcefully.
C) Muscle tissue can get shorter, but cannot get longer.
D) Muscle tissue can get longer, but cannot get shorter.
E) None of these statements are true.

Question 18

Which type of muscle tissue causes peristalsis?

A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle

Question 19

Which type of muscle tissue is autorhythmic?

A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
D) Both skeletal and cardiac muscle are correct.
E) Both cardiac and smooth muscle are correct.

Question 20

Which type of muscle tissue possesses striations?

A) Skeletal muscle
B) Smooth muscle
C) Cardiac muscle
D) Both skeletal and cardiac muscle are correct.
E) Both cardiac and smooth muscle are correct.

Question 21

Troponin

A) has two subunits.
B) is part of the myosin myofilament.
C) is a long, flexible protein.
D) has a calcium-binding site.
E) binds to ATP.

Question 22

Which of the following connective tissue layers is outside all the others?

A) Perimysium
B) Endomysium
C) Epimysium
D) Paramysium
E) Sarcolemma

Question 23

Epimysium

A) surrounds individual muscles.
B) separates muscle fibers.
C) connects muscles to bone.
D) is a type of muscle tissue.
E) is a type of nerve tissue.

Question 24

Which of the following is mismatched?

A) I band - contains only actin
B) M line - middle of the H zone
C) Z disk - structure between adjacent sarcomeres
D) Myosin myofilaments - thin myofilaments
E) Actin myofilaments - thin myofilaments

Question 25

Which of the following is NOT a property of the myosin head?

A) They form cross-bridges with the active sites of actin.
B) They have a hinge region to bend and straighten.
C) They bind to troponin.
D) They have ATPase activity.
E) They bind to ATP.

Question 26

Which of the following is part of a thin myofilament?

A) ATP-binding site
B) Globular (G) actin
C) Calcium
D) Myosin
E) Sarcolemma

Question 27

Myosin is also known as the

A) thick myofilament.
B) thin myofilament.
C) intermediate myofilament.
D) short myofilament.
E) sarcomere.

Question 28

Muscle myofibrils

A) are found in the sarcolemma.
B) extend from the sarcolemma to the T-tubule.
C) contain myosin and actin myofilaments.
D) hold muscle fibers together.
E) do not appear striated.

Question 29

List the following structures in order from smallest to largest.
(1) Muscle fiber
(2) Myofilament
(3) Myofibril
(4) Muscle fascicle

A) 4, 2, 3, 1
B) 2, 1, 4, 3
C) 3, 1, 4, 2
D) 2, 3, 1, 4
E) 1, 2, 3, 4

Question 30

The active sites to which cross-bridges attach are found on the

A) sarcoplasmic reticulum.
B) actin myofilaments.
C) Z disks.
D) T tubules.
E) myosin myofilaments.

Question 31

Endomysium is a delicate network of loose connective tissue that

A) surrounds each muscle fiber.
B) forms a sheath around a fascicle.
C) is composed of elastic fibers.
D) separates individual muscles.
E) penetrates muscle fibers.

Question 32

A sarcomere is the

A) plasma membrane of a muscle fiber.
B) cytoplasm of a muscle fiber.
C) structural and functional unit of the skeletal muscle fiber.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin or myosin.

Question 33

ATPase is found in

A) F-actin strands.
B) G-actin globular units.
C) myosin heads.
D) tropomyosin grooves.
E) troponin molecules.

Question 34

Which of the following is true about skeletal muscle?

A) Sensory neurons stimulate muscles to contract.
B) There are very few blood vessels in skeletal muscle.
C) Every muscle fiber receives a branch of an axon from the nerve.
D) There are very few nerve fibers in a muscle.
E) All of the choices are true.

Question 35

The region of the sarcomere that contains both actin and myosin myofilaments is called the

A) I band.
B) A band.
C) Z disk.
D) H zone.
E) M line.

Question 36

A fascicle

A) is a bundle of reticular fibers.
B) is surrounded by perimysium.
C) is only found in smooth muscle.
D) possesses an external lamina.
E) is a bundle of collagen fibers.

Question 37

Actin myofilaments

A) resemble bundles of minute golf clubs.
B) contain both myosin and tropomyosin.
C) are held in place by the M line.
D) contain strands of fibrous actin.
E) are the thickest proteins in muscle.

Question 38

Which of the following is composed of myosin molecules?

A) Thick myofilaments
B) I bands
C) Z disks
D) Sarcolemma
E) Tropomyosin

Question 39

Skeletal muscle develops from cells called

A) fascicles.
B) myoblasts.
C) myofibrils.
D) myotomes.
E) fasciculi.

Question 40

A sarcomere extends from

A) one Z disk to an adjacent Z disk.
B) one T tubule to the next T tubule.
C) the middle of the I band to the middle of the A band.
D) the H zone to the I band.
E) the M line to the next M line.

Question 41

Which of the following statements regarding the sliding filament model is false?

A) Actin and myosin do not shorten during contraction.
B) Both actin and myosin myofilaments shorten during contraction.
C) The sarcomere shortens.
D) The I band and H zones become narrower during contraction.
E) The A band remains constant in length.

Question 42

In which of the following situations does a resting membrane potential exist?

A) A relaxed muscle fiber
B) A conducting neuron
C) A stimulated sensory receptor in the skin
D) A contracting cardiac muscle cell
E) The eye seeing an image

Question 43

Sarcoplasm is the

A) plasma membrane of a muscle fiber.
B) cytoplasm of a muscle fiber.
C) structural and functional unit of the skeletal muscle fiber.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin or myosin.

Question 44

Which of the following changes have the potential to dramatically affect the potential difference across the plasma membrane?

A) Increased permeability of the membrane to Na⁺
B) Increased intracellular concentration of K⁺
C) Any change in the rate at which the sodium-potassium pump works
D) Increased permeability of the membrane to Na⁺ and increased intracellular concentration of K⁺
E) Increased permeability of the membrane to Na⁺, increased intracellular concentration of K⁺, and any change in the rate at which the sodium-potassium pump works

Question 45

The electrical properties of cells are the result of

A) ion concentration differences across the plasma membrane.
B) receptor sites that are present on the plasma membrane.
C) phosphorylation reactions within the cytoplasm.
D) phospholipids in the plasma membrane.
E) None of these choices are correct.

Question 46

The model that describes the contraction of the muscle is called the

A) contraction cycle.
B) power stroke.
C) sliding filament model.
D) slipping fibril mechanism.
E) paddle model.

Question 47

A myofibril is the

A) plasma membrane of a muscle fiber.
B) cytoplasm of a muscle fiber.
C) structural and functional unit of the skeletal muscle fiber.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin.

Question 48

A stimulus either causes an action potential or it doesn't. This is called

A) an all-or-none response.
B) a graded response.
C) a latent period response.
D) a relative refractory response.
E) an arbitrary response.

Question 49

When repolarization of the plasma membrane is complete, the

A) cell dies.
B) cell regenerates.
C) cell no longer has a potential difference across its membrane.
D) cell is no longer responsive.
E) original polarity of the cell is restored.

Question 50

The length of the resting sarcomere is

A) longer than the length of a contracted sarcomere.
B) shorter than the length of a contracted sarcomere.
C) the same length as a contracted sarcomere.
D) the same length as the muscle fiber.
E) the same length as the myofibril.

Question 51

Which of the following situations occurs in electrically excitable cells?

A) When Na⁺ ion channels open, K⁺ ion channels close.
B) The sodium-potassium pump moves sodium into the cell.
C) Depolarization causes voltage-gated sodium ion channels to open.
D) Sodium ion channels are opened by high extracellular calcium levels.
E) The opening and closing of ligand-gated channels cause depolarization.

Question 52

The plasma membrane of an excitable cell is more permeable to K⁺ because

A) of its positive electrical charge.
B) there are more leak ion channels for K⁺ than Na⁺.
C) protein molecules cannot exit through the plasma membrane.
D) calcium ions block Na⁺ and Cl^- channels.
E) there are more gated channels for K⁺.

Question 53

A myofilament is the

A) plasma membrane of a muscle fiber.
B) cytoplasm of a muscle fiber.
C) structural and functional unit of the skeletal muscle fiber.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin or myosin.

Question 54

An action potential

A) occurs when the local potential reaches threshold level.
B) is not propagated.
C) has no repolarization phase.
D) is an example of negative feedback.
E) can be of varying strengths depending on strength of the stimulus.

Question 55

Channels that open or close in response to changes in the electrical charge or voltage across the plasma membrane are called

A) ligand-gated ion channels.
B) leak ion channels.
C) relegated ion channels.
D) voltage-gated ion channels.
E) obligated ion channels.

Question 56

The sarcolemma is the

A) plasma membrane of a muscle fiber.
B) cytoplasm of a muscle fiber.
C) structural and functional unit of the skeletal muscle fiber.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin.

Question 57

Which of the following is true during the resting membrane potential?

A) Sodium ion concentration is greater inside cells.
B) Negatively charged proteins are more concentrated outside the cell.
C) A greater concentration of calcium ions is found inside the cell.
D) Potassium is concentrated primarily inside the cell.
E) None of these choices reflect what occurs during the resting membrane potential.

Question 58

Which of the following causes an unequal ion concentration across the resting plasma membrane?

A) The functioning of the sodium-chloride pump
B) Negatively charged proteins not readily diffusing across the plasma membrane
C) The attraction of chloride ions to other intracellular anions
D) The repulsion of potassium ions by the intracellular anions
E) The attraction of sodium ions to chloride ions

Question 59

The outside of the resting plasma membrane is ________ relative to the inside of the resting plasma membrane.

A) positively charged
B) negatively charged
C) electrically neutral
D) recharged
E) None of these choices are correct.

Question 60

Depolarization of the plasma membrane occurs when there is a rapid influx (inflow) of

A) potassium ions.
B) chloride ions.
C) calcium ions.
D) sodium ions.
E) amino acids.

Question 61

In excitation-contraction coupling,

A) Ca²⁺ must bind with myosin to expose active sites on actin.
B) myosin heads bind to exposed active sites on actin.
C) cross-bridges form between myosin heads and Ca²⁺.
D) movement of the troponin-tropomyosin complex causes actin myofilaments to slide.
E) ATP binds to actin myofilaments.

Question 62

A muscle fiber will respond to a stimulus when that stimulus reaches the ________ level.

A) threshold
B) relaxation
C) rigor mortis
D) recruitment
E) resting

Question 63

The sites where a chemical substance is transmitted from the presynaptic terminal of an axon to the postsynaptic membrane of a muscle fiber are called

A) neuromuscular junctions.
B) sarcomeres.
C) myofilaments.
D) Z disks.
E) cell bodies of neurons.

Question 64

Too much acetylcholinesterase causes

A) continuous stimulation of the muscle fiber.
B) rapid degradation of acetylcholine.
C) voltage-gated Ca²⁺ channels opening in the presynaptic terminal.
D) an increase in Na⁺ uptake by the muscle fiber.
E) exocytosis of synaptic vesicles.

Question 65

Acetylcholine is released from the presynaptic terminal by the process of

A) exocytosis.
B) diffusion.
C) phagocytosis.
D) active transport.
E) endocytosis.

Question 66

One ATP molecule is required for

A) formation of the cross-bridge.
B) movement of the cross-bridge.
C) release of the cross-bridge.
D) formation of the cross-bridge and for movement of the cross-bridge.
E) formation of the cross-bridge, for movement of the cross-bridge, and for release of the cross-bridge.

Question 67

T tubules

A) provide nutrients to the muscle fiber.
B) generate new muscle fibers.
C) conduct action potentials deep into the muscle fiber.
D) release acetylcholine.
E) store calcium ions.

Question 68

In order for muscle relaxation to occur,

A) Ca²⁺ must be transported to troponin.
B) power strokes slow down.
C) the active sites on actin must be blocked.
D) Na⁺ must be actively transported to troponin.
E) the active sites on myosin must be uncovered.

Question 69

Which of the following structures contains the other four items listed?

A) Postsynaptic membrane
B) Presynaptic terminal
C) Synaptic cleft
D) Neuromuscular junction
E) Receptors on postsynaptic membrane

Question 70

If Na⁺ cannot enter a muscle fiber in response to a stimulus,

A) contraction cannot occur.
B) relaxation cannot occur.
C) Na⁺ will be released from the sarcoplasmic reticulum instead.
D) the active sites are left exposed.
E) the action potential travels into the muscle anyway.

Question 71

When an action potential reaches the presynaptic terminal,

A) calcium ions diffuse into the presynaptic terminal through voltage-gated ion channels.
B) acetylcholine moves into the presynaptic terminal.
C) a local potential is generated in the presynaptic terminal.
D) ligand-gated ion channels in the presynaptic terminal are opened.
E) nothing else happens.

Question 72

Arrange the following list of biochemical events in the correct sequence.
(1) An action potential is conducted deep into the muscle fiber by the T tubule.
(2) Calcium ions bind to troponin.
(3) The membranes of the sarcoplasmic reticulum become more permeable to calcium ions.
(4) Calcium ions diffuse into the sarcoplasm around the myofibril.
(5) The troponin-tropomyosin complex moves exposing active sites.

A) 1, 5, 2, 3, 4
B) 1, 3, 4, 2, 5
C) 1, 2, 3, 4, 5
D) 1, 3, 2, 5, 4
E) 1, 4, 3, 2, 5

Question 73

When the myosin head flexes into a bend, pulling the actin filament along with it, this is called the

A) action reaction.
B) power stroke.
C) recovery stroke.
D) muscle tone.
E) action potential.

Question 74

Synaptic vesicles in the neuromuscular junction contain

A) calcium.
B) ATP.
C) acetylcholine.
D) acetylcholinesterase.
E) sodium.

Question 75

Arrange these structures as they participate in excitation-contraction.

A) T tubules, sarcolemma, Ca²⁺, sarcoplasmic reticulum
B) Ca²⁺, T tubules, sarcolemma, sarcoplasmic reticulum
C) Sarcolemma, T tubules, sarcoplasmic reticulum, Ca²⁺
D) Sarcoplasmic reticulum, Ca²⁺, T tubules, sarcolemma
E) Sarcolemma, sarcoplasmic reticulum, Ca²⁺, T tubules

Question 76

T tubules are invaginations of the

A) sarcoplasmic reticulum.
B) sarcomere.
C) myofibril.
D) sarcoplasm.
E) sarcolemma.

Question 77

The sarcoplasmic reticulum

A) stores Ca²⁺.
B) shortens during muscle contraction.
C) transmits nerve impulses to the myofibrils.
D) connects adjacent sarcomeres.
E) covers the muscle fiber.

Question 78

Which of the following events occurs on the postsynaptic membrane?

A) Acetylcholine production
B) Rapid degradation of acetylcholine
C) Release of neurotransmitter
D) Neurotransmitter combines with a receptor molecule
E) Release of Ca²⁺

Question 79

Lack of acetylcholinesterase in the synaptic cleft would result in

A) a decrease in acetylcholine production by the motor neuron.
B) continuous stimulation of the postsynaptic membrane.
C) rapid degradation of acetylcholine.
D) relaxation of the muscle.
E) continuous stimulation of the presynaptic membrane.

Question 80

Acetylcholine binds to a membrane bound receptor and causes ligand-gated sodium channels to open and results in

A) hyperpolarization.
B) depolarization.
C) hypoplarization.
D) no change in membrane potential.
E) There is not enough information to predict the outcome.