Deck 9: Muscular System: Histology and Physiology

Question 1

Which type of muscle tissue possesses striations?

A) skeletal muscle
B) smooth muscle
C) cardiac muscle
D) both skeletal and cardiac muscle
E) both cardiac and smooth muscle

Answer 1

D

Question 2

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.

Answer 2

E

Question 3

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.

Answer 3

A

Question 4

What type of muscle tissue causes peristalsis?

A) skeletal muscle
B) smooth muscle
C) cardiac muscle

Question 5

Which of the following 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

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.

Question 7

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 can not get longer.
D) Muscle tissue can get longer, but can not get shorter.
E) None of these statements are true.

Question 8

Which type of muscle tissue is multinucleated?

A) skeletal muscle
B) smooth muscle
C) cardiac muscle
D) both skeletal and cardiac muscle
E) both cardiac and smooth muscle

Question 9

Which type of muscle tissue is autorhythmic?

A) skeletal muscle
B) smooth muscle
C) cardiac muscle
D) both skeletal and cardiac muscle
E) both cardiac and smooth muscle

Question 10

Which type of muscle tissue has spindle-shaped cells?

A) skeletal muscle
B) smooth muscle
C) cardiac muscle
D) both skeletal and cardiac muscle
E) both cardiac and smooth muscle

Question 11

What type of muscle tissue has neuromuscular junctions?

A) skeletal muscle
B) smooth muscle
C) cardiac muscle

Question 12

Which type of muscle tissue causes contraction of the heart?

A) skeletal muscle
B) smooth muscle
C) cardiac muscle

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

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

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

Question 15

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 16

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 17

What type of muscle tissue causes vasoconstriction?

A) skeletal muscle
B) smooth muscle
C) cardiac muscle

Question 18

Which type of muscle tissue has cells that branch?

A) skeletal muscle
B) smooth muscle
C) cardiac muscle
D) both skeletal and cardiac muscle
E) both cardiac and smooth muscle

Question 19

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 20

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

A) skeletal muscle
B) smooth muscle
C) cardiac muscle

Question 21

Fascia

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 22

Myosin is also known as the

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

Question 23

Which of the following is composed of myosin molecules?

A) thick myofilaments
B) I Bands
C) Z disks
D) sarcolemma
E) tropomyosin

Question 24

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

A) perimysium
B) endomysium
C) epimysium
D) paramysium
E) sarcolemma

Question 25

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 26

Skeletal muscle develops from multinucleated cells called

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

Question 27

ATPase is found in

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

Question 28

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 these are true.

Question 29

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 30

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 31

List the following structures in order from smallest to largest. (1) muscle fiber
(2) myofilament
(3) myofibril
(4) muscle fasciculus

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 32

Endomysium is a delicate network of loose connective tissue that

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

Question 33

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 34

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 35

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 36

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 cells together.
E) do not appear striated.

Question 37

A fasciculus

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 38

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 39

A sarcomere is the

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

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

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 42

The plasma membrane of an excitable cell is more permeable to potassium ions 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 cell membrane.
D) calcium ions block Na+ and Cl- channels.
E) there are more gated channels for K+.

Question 43

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 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 sodium ions
B) increased intracellular concentration of potassium ions
C) any change in the rate at which the sodium-potassium pump works
D) increased permeability of the membrane to sodium ions and increased intracellular concentration of potassium ions
E) increased permeability of the membrane to sodium ions, increased intracellular concentration of potassium ions and any change in the rate at which the sodium-potassium pump works

Question 45

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 is correct.

Question 46

The sarcolemma is the

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

Question 47

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 do not readily diffuse 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 48

A myofilament is the

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

Question 49

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 50

A myofibril is the

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

Question 51

Sarcoplasm is the

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

Question 52

Depolarization of the cell 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 53

When repolarization of the cell 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 54

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 55

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 56

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 cell membrane.
E) None of these choices is correct.

Question 57

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 58

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 59

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 60

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 61

Arrange these structures as they participate in excitation-contraction.

A) T tubules, sarcolemma, calcium ions, sarcoplasmic reticulum
B) calcium ions, T tubules, sarcolemma, sarcoplasmic reticulum
C) sarcolemma, T tubules, sarcoplasmic reticulum, calcium ions
D) sarcoplasmic reticulum, calcium ions, T tubules, sarcolemma
E) sarcolemma, sarcoplasmic reticulum, calcium ions, T tubules

Question 62

The sarcoplasmic reticulum

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

Question 63

In order for muscle relaxation to occur,

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

Question 64

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 65

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 calcium ions

Question 66

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 67

Synaptic vesicles in the neuromuscular junction contain

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

Question 68

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 69

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 70

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 71

T tubules are invaginations of the

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

Question 72

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.

Question 73

T tubules

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

Question 74

In excitation-contraction coupling,

A) calcium ions 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 calcium ions.
D) movement of the troponin-tropomyosin complex causes actin myofilaments to slide.
E) ATP binds to actin myofilaments.

Question 75

Too much acetylcholinesterase causes

A) continuous stimulation of the muscle fiber.
B) rapid degradation of acetycholine.
C) voltage-gated calcium ion channels opening in the presynaptic terminal.
D) an increase in sodium uptake by the muscle fiber.
E) exocytosis of synaptic vesicles.

Question 76

If sodium ions cannot enter a muscle fiber in response to a stimulus,

A) contraction cannot occur.
B) relaxation cannot occur.
C) sodium ions 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 77

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 body of neuron.

Question 78

Acetylcholine is released from the presynaptic terminal by the process of

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

Question 79

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 80

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