Deck 9: Muscular System: Histology and Physiology

Question 1

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

Answer 1

D

Question 2

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

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

Answer 2

A

Question 3

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

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 type of muscle tissue causes contraction of the heart?

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

Question 6

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 7

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

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

Question 8

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 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
E)both cardiac and smooth muscle

Question 10

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 11

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 12

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

Question 13

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 14

What type of muscle tissue causes vasoconstriction?

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

Question 15

What type of muscle tissue causes peristalsis?

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

Question 16

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 17

What type of muscle tissue has neuromuscular junctions?

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

Question 18

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 19

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 20

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 21

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 22

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 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

Myosin is also known as the

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

Question 25

ATPase is found in

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

Question 26

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 27

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 28

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 29

Skeletal muscle develops from multinucleated cells called

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

Question 30

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 31

Which of the following is composed of myosin molecules?

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

Question 32

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 33

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 34

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 35

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 36

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 37

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 38

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 39

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

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

Question 40

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 41

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 42

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 43

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 44

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 45

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 46

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 47

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 48

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 49

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 50

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 51

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 52

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 53

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 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

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 56

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 57

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 58

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 59

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 60

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 61

Synaptic vesicles in the neuromuscular junction contain

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

Question 62

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 63

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 64

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 65

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 66

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 67

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 68

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 69

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 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

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 72

Acetylcholine is released from the presynaptic terminal by the process of

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

Question 73

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 74

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 75

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 76

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 77

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 78

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 79

T tubules are invaginations of the

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

Question 80

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.