Ch 9 Muscle & Muscle Tissue

Front 1

In a neuromuscular junction, synaptic vesicles in the motor neuron contain which neurotransmitter?

Back 1

Acetylcholine

Front 2

When an action potential arrives at the axon terminal of a motor neuron, which ion channels open?

Back 2

voltage-gated calcium channels

Front 3

What means of membrane transport is used to release the neurotransmitter into the synaptic cleft?

Back 3

exocytosis

Front 4

The binding of the neurotransmitter to receptors on the motor end plate causes which of the following to occur?

Back 4

binding of the neurotransmitter causes chemically gated sodium channels to open in the motor end plate

Front 5

How is acetylcholine removed from the synaptic cleft?

Back 5

diffusion away from the synaptic cleft

Front 6

The action potential on the muscle cell leads to contraction due to the release of calcium ions. where are calcium ions stored in the muscle cell?

Back 6

terminal cisternae of the sarcoplasmic reticulum

Front 7

What causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum within a muscle cell?

Back 7

arrival of an action potential

Front 8

The binding of calcium to which molecule causes the myosin binding sites to be exposed?

Back 8

Troponin

Front 9

When calcium binds to _____, _____ releases tropomysoin, exposing the myosin binding sites.

Back 9

Troponin

Front 10

A myosin head binds to which molecule to form a cross bridge?

Back 10

actin

Front 11

What causes the myosin head to disconnect from actin?

Back 11

Binding of ATP

Front 12

What energizes the power stroke?

Back 12

hydrolysis of ATP

Front 13

Excitation - contraction coupling is a series of events that occur after the events of the neuromuscular junction have transpired. The term excitation refers to which step in the process?

Back 13

Excitation refers to propagation od action potentials along the sarcolemma

Front 14

Excitation of the sarcolemma is coupled or linked to the contraction of a Skeletal muscle fiber. What specific event initiates the contraction?

Back 14

Calcium release from the sarcoplasmic reticulum initiates the contraction

Front 15

A triad is composed of T tubules and 2 adjacent terminal cisternae of the sarcoplasmic reticulum. How are these components connected?

Back 15

a series of proteins that control calcium release

Front 16

What is the name given to the regulary spaced infoldings of the sarcolemma?

Back 16

Transverse or T Tubules

Front 17

Which of the following is most directly responsible for the coupling of excitation to contraction of Skeletal muscle fibers?

Back 17

Calcium ions

Front 18

What is the relationship between the number of motor neurons recruited and the number of Skeletal muscle fibers innervated?

Back 18

hundreds of Skeletal muscle fibers are innervated by a single motor neuron

Front 19

Contraction. of Skeletal muscle is controlled by

Back 19

somatic motor neurons

Front 20

Skeletal muscle lacks the coarse connective tissue sheaths that are found in smooth muscle?

Back 20

false

Front 21

Skeletal muscle fibers tend to be shorter than smooth muscle fibers?

Back 21

false

Front 22

Skeletal muscles have one nucleus, but smooth muscle cells are multi-nucleated?

Back 22

false

Front 23

Skeletal muscle fibers contain sarcomeres; smooth muscle fibers do not.

Back 23

true

Front 24

Myasthenia gravis is sometimes treated medically by a treatment that involves

Back 24

inhibiting the action of acetylcholinesterase

Front 25

Skeletal muscles use creatine phosphate instead of ATP

Back 25

false

Front 26

Skeletal muscles have t tubules

Back 26

true

Front 27

Skeletal muscles are multi-nucleated

Back 27

true

Front 28

Skeletal muscle cells contain myoglobin

Back 28

true

Front 29

Skeletal muscles cells have glycosomes

Back 29

true

Front 30

outer most connective tissue sheaths are continuous with what?

Back 30

tendon

Front 31

Which muscle characteristics describes the ability of a muscle to respond to stimulus?

Back 31

excitability

Front 32

The response of a motor unit to a single action potential of its motor neuron is called

Back 32

a muscle twitch

Front 33

Which of the following factors influence the velocity and duration of muscle contraction?

Back 33

load placed on the muscle

Front 34

The distance between z disc's ____ during muscle contraction?

Back 34

decreases

Front 35

The sliding filament model of contraction states that

Back 35

During contraction, the thin myofilaments slide past the thick myofilaments so that the actin and myosin myofilaments overlap to a greater degree

Front 36

a muscle that is lengthening while it prices tension is performing an ______ contraction

Back 36

eccentric

Front 37

Binding of calcium to calmodulin is a step in excitation - contraction coupling of _____ cells.

Back 37

smooth muscle

Front 38

What specific neurotransmitter is released from the axonal terminus via exocytosis?

Back 38

acetylcholine

Front 39

When muscle cells break down glucose to generate ATP under oxygen deficient conditions, they will form

Back 39

lactic acid

Front 40

The major role of sarcoplasmic reticulum is to regulate

Back 40

intracellular levels of Ca2+

Front 41

Which type of muscle cannot contract without being stimulated by the nervous system?

Back 41

Skeletal

Front 42

Which pathway for regenerating ATP provides the majority of the energy used for muscle activity during 30 minute of light to moderate exercise?

Back 42

aerobic respiration

Front 43

Which event is the most significant in initiating the wave of depolarization?

Back 43

diffusion of Na+ into the muscle fiber

Front 44

binding of acetylcholine to its receptor open ______ that allow Na+ and K+ to diffuse across the sarcolemma.

Back 44

chemically gated ion channels

Front 45

Duchenne muscular dystrophy could theoretically be cured if

Back 45

none of the above

Front 46

The A Band is occupier by the entire length of

Back 46

thick myofilaments

Front 47

slow oxidative muscle fibers are best suited for

Back 47

running a marathon

Front 48

The first step toward generating a Skeletal muscle contraction is

Back 48

stimulation of the muscle by a nerve ending

Front 49

The connective tissue sheaths of Skeletal muscle in order from internal to external are

Back 49

endomysium, perimysium, and epimysium

Front 50

Which muscle fiber is best suited for endurance activities like jogging?

Back 50

slow oxidative fibers

Front 51

a fascicle is an organized group of muscle fibers bound by a

Back 51

perimysium

Front 52

The smallest contractile unit of a muscle fiber is

Back 52

The sarcomere

Front 53

If both neurons were activated, more muscle fibers would contract than if either neuron alone were active. This mechanism for control of the force of muscle contraction is known as

Back 53

recruitment

Front 54

The force of a muscle contraction is not affected by

Back 54

The amount of atp stored in the muscle cells

Front 55

What is a cross bridge cycle?

Back 55

cycle in which an energized myosin head binds to actin and performs a power stroke, then binds to atp in order to detach and re - energize

Front 56

Thick myofilaments are made of

Back 56

myosin

Front 57

Which of the following is the smallest structural unit in which the distinctive striated bands characteristic of Skeletal muscle are observed?

Back 57

myofibrils

Front 58

In bedridden patients recovering from a badly fractured femur, disuse atrophy in the thigh muscles is caused by

Back 58

decreased synthesis of muscle proteins and or increased breakdown of muscle proteins

Front 59

What event directly triggers the release of neurotransmitter from the synaptic vesicles in the axon terminal?

Back 59

diffusion of Ca2+ into the axon terminus

Front 60

Which protein inhibits interaction between actin and myosin to prevent Skeletal muscle contraction; and which ions remove the inhibition?

Back 60

tropomyosin; calcium ions

Front 61

Cross bridge formation between myosin heads and actin molecules is caused by the elevation of calcium ion concentration in the cytosol. During rigor mortis, thus elevation of calcium ion concentration in the cytosol is permanent because

Back 61

mitochondria stop producing atp molecules required by the sarcoplasmic reticulum's calcium ion pumps

Front 62

Muscle tissue does not

Back 62

produce blood cells

Front 63

Which of the following is correctly paired?

Back 63

Skeletal muscle: voluntary control

Front 64

Excitation contraction coupling I codes all except which of the following events?

Back 64

release of acetylcholine from axon terminals at the neuromuscular junction

Front 65

The dense connective tissue of the epimysium is continous with the _______ that connects the muscle to a bone.

Back 65

Tendon

Front 66

Marathon Runner

Back 66

anaerobic pathway

Front 67

Weight Lifting

Back 67

aerobic pathway

Front 68

25 meter swim

Back 68

direct phosphorylation

Front 69

Muscle tissue has all of the following properties except

Back 69

secretion

Front 70

The force of muscle contraction is controlled by multiple motor unit summation or recruitment.

Back 70

true

Front 71

The muscle cell membrane is called the

Back 71

sarcolemma

Front 72

The end of the muscle that typically moves when a muscle contracts is called the

Back 72

insertion

Front 73

Which of the choices below does not secs rive how excess post exercise oxygen consumption restores metabolic conditions?

Back 73

increases the level of lactic acid in the muscle

Front 74

Once a motor neuron is fired, all the muscle fibers in a muscle contract

Back 74

false

Front 75

______ stores oxygen in muscle cells.

Back 75

myoglobin

Front 76

The thin filaments actin contain a polypeptide subunit G actin that bears active sites for myosin attachment.

Back 76

true

Front 77

Which of the following is the correct sequence of events for muscle contractions?

Back 77

motor neuron action potential, neurotransmitter release, muscle cell action potential, release or calcium ions from SR, ATP-driven power stroke, sliding of myofilaments

Front 78

Which of the following is not a component of the standard treatment for muscle strain?

Back 78

stretching of the muscle

Front 79

a contraction in which the muscle does not shorten but its tension increases is called isometric contraction

Back 79

true

Front 80

During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to

Back 80

lactic acid

Front 81

cardiac muscle has a limited regenerative capacity

Back 81

true

Front 82

The sliding filament model of contraction involves

Back 82

actin and myosin sliding past each other and partially overlapping

Front 83

In an isotonic contraction, the muscle

Back 83

changes in length and moves the load

Front 84

What is the primary function of eave summation?

Back 84

produce smooth, continuous muscle contraction

Front 85

excitation contraction coupling directly requires which substances?

Back 85

Ca2+

Front 86

The oxygen binding protein found in muscle cells is

Back 86

myoglobin

Front 87

Which of the following is not a connective tissue sheaths that wraps individual muscle fibers?

Back 87

a pone u roses

Front 88

What muscle cells have the greatest ability to regenerate?

Back 88

smooth

Front 89

Which is the role of calcium ions in muscle contraction?

Back 89

bind to regulatory sites on troponin to remove contraction inhibition

Front 90

One of the important functions of Skeletal muscle contraction is production of heat.

Back 90

true

Front 91

a motor neuron and all the muscle cells that it stimulates are referred to as a motor end plate

Back 91

false

Front 92

Only _____ muscle cells are always multi-nucleated.

Back 92

Skeletal

Front 93

What is the role of tropomysoin in Skeletal muscles?

Back 93

serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules

Front 94

Which of the following would be recruited later In muscle stimulation when contractile strength increases?

Back 94

motor units with larger, less excitable neurons

Front 95

Muscle contraction will always promote movement of body pars regardless of how they are attached.

Back 95

false

Front 96

eccentric contractions are more forceful than concentric contractions.

Back 96

true

Front 97

What does excess post exercise oxygen consumption represent?

Back 97

tbe difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used

Front 98

The giant protein titin maintains the organization of the ______ assisting in muscle stretching

Back 98

band

Front 99

Muscle cells store more creative phosphate than atp resulting in the muscle having a reserve source of energy.

Back 99

true

Front 100

immediately following the arrival of the stimulus at a Skeletal muscle cell there is a short period called the _______ period during which the neurotransmitter is released by exocytosis, diffuses across the synaptic cleft, and binds to its receptor.

Back 100

latent

Front 101

hypothetically, it a muscle were stretched to the point where thick and thin filaments no longer overlapped

Back 101

No muscle tension could be generated

Front 102

What structure in Skeletal muscle cells functions in calcium storage?

Back 102

sarcoplasmic reticulum

Front 103

What is the most distinguishing characteristic of muscle tissue?

Back 103

The ability to transform chemical energy into mechanical energy

Front 104

What is the role of tropomyosin in Skeletal muscles?

Back 104

serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules

Front 105

Muscle tone is

Back 105

a state of sustained partial contraction

Front 106

When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods?

Back 106

refractory periods

Front 107

3 discrete types of muscle fibers are identified on the basis of their size, speed, and endurance. which of the following athletic endeavors best represents the use of red fibers?

Back 107

a long relaxing swim