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Final Lab & Lecture Exam > Chapter 10 > Flashcards

Chapter 10 Flashcards

1
Q

The three types of cells in muscle tissue are

A
  • skeletal
  • cardiac
  • smooth
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2
Q

What function do all three muscle tissue types share in common?

A

generating a force called muscle tension

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3
Q
  • create movement
  • maintain posture
  • stabilize joints
  • generate heat
  • regulate the flow of materials through hollow organs
A

other functions of muscle tissue

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4
Q

due to their length and appearance muscle cells are known as

A

fibers

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5
Q
  • made up of long muscle cells arranged parallel to one another; some are quite long, extending nearly the entire length of the muscle
  • they are multinucleated cells whose contractions arevoluntary (controlled by conscious thought)
A

skeletal muscle

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6
Q
  • muscle cells are found only in the heart
  • Each cell is short and highly branched, and has one to two nuclei
  • Intercalated discs join adjacent cells; they contain gap junctions and desmosomes (modified tight junctions) that both unite the cells and permit them to coordinate contraction
  • Contraction is involuntary, or not controlled by conscious thought
A

cardiac muscle

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7
Q
  • muscle cells are long and flat with “spindle-shaped” pointed ends and a single centrally located nucleus
  • muscle cells are found lining most hollow organs in the eye, skin, and some glandular ducts; their contractions are involuntary
A

smooth muscle cells

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8
Q

What makes smooth muscle cells different from skeletal and cardiac muscle tissues?

A

consists of nonstriated smooth muscle cells

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9
Q

What are the five properties of muscle cells?

A
  • contractility
  • excitability
  • conductivity
  • extensibility
  • elasticity
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10
Q

the ability to contract where proteins in the cell draw closer together; this does not necessarily involve shortening of the cell

A

contractility

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11
Q

the ability of a cell to respond to a stimulus (chemical, mechanical stretch, or local electrical signals)

A

excitability

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12
Q

the ability of a cell to conduct electrical changes across the entire plasma membrane

A

conductivity

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13
Q

the ability of a cell that allows it to be stretched without being ruptured (up to 3 times their resting length without damage)

A

extensibility

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14
Q

the ability of a cell that allows it to return to its original length after it has been stretched

A

elasticity

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15
Q

or muscle cells, are described using specialized terminology

A

myocytes

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16
Q

the myocyte’s cytoplasm

A

sarcoplasm

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17
Q

the myocyte’s plasma membrane

A

sarcolemma

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18
Q

is modified endoplasmic reticulum that:
Forms a weblike network surrounding the myofibrils
Varies in structure in the three types of muscle tissue (discussed later)

A

sarcoplasmic reticulum

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19
Q
  • cylindrical organelles found in each of the three muscle cell types
  • made up of bundles of specialized proteins that allow for contraction
A

myofibrils

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20
Q

the most abundant organelle, are made up of mostly contractile proteins

A

myofibrils

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21
Q

surrounds the myofibrils and stores and releases calcium ions

A

The sarcoplasmic reticulum (SR)

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22
Q
  • are deep inward extensions of sarcolemma that surround each myofibril
  • form a tunnel-like network within the musclefiber, continuous with the exterior of the cell, and are therefore filled with extracellular fluid
A

Transverse tubules (T-tubules)

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23
Q

enlarged sections of SR found flanking each T-tubule

A

terminal cisternae

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24
Q

Two terminal cisternae and their corresponding T-tubule form

A

triad

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25
Q

made of hundreds to thousands of myofilaments, including contractile proteins, regulatory proteins, and structural proteins

A

myofibrils

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26
Q

generate tension

A

contractile proteins

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27
Q

dictate when a fiber may contract

A

regulatory proteins

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28
Q

maintain proper alignment and fiber stability

A

structural proteins

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29
Q

what are the three types of myofilaments?

A
  • thick
  • thin
  • elastic
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30
Q

composed of bundles of the contractile protein myosin

A

thick filaments

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31
Q

composed of the proteins actin, tropomyosin, and troponin

A

thin filaments

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32
Q

composed of a single massive, spring-like structural protein called titin that stabilizes the myofibril structure and resists excessive stretching force

A

elastic filaments

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33
Q

a contractile protein that has active sites that bind with the myosin heads of thick filaments

A

actin

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34
Q

a long rope-like regulatory protein that twist around two strands of actin, covering active sites.

A

tropomyosin

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35
Q

a small globular regulatory protein that holds tropomyosin in place and assists with turning contractions on and off

A

troponin

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36
Q
  • degenerative muscular disease occurring almost exclusively in boys
  • Caused by a defective gene for the protein dystrophin, coded on X chromosome
A

Duchenne Muscular Dystrophy (DMD)

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37
Q

In the absence of normal dystrophin, the sarcolemma breaks down and the muscle fiber is destroyed and replaced with fatty and fibrous connective tissue

A

Duchenne Muscular Dystrophy (DMD)

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38
Q

Multiple muscle fibers (surrounded by extracellular matrix called the endomysium) form a

A

fascicle

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39
Q

Each fascicle is surrounded by a layer of connective tissue called the

A

perimysium

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40
Q

Bundles of fascicles make up a

A

skeletal muscle

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41
Q

a skeletal muscle is surrounded by

A

epimysium

42
Q

The perimysium and epimysium come together at the end of the muscle to form

A

tendon

43
Q

binds the muscle to its attaching structure (usually bone)

A

tendon

44
Q

Skeletal muscles are enclosed by a layer of thick connective tissue called

A

fascia

45
Q

where only thin filaments are found

A

light bands

46
Q

where both thin and thick filamentsare found

A

dark bands

47
Q

in light, mnemonic) is composed only of thin filaments

A

I bands

48
Q

is a dark line in the middle of the A band made up of structural proteins that hold the thick filaments in place and serve as an anchoring point for elastic filaments

A

M line

49
Q

contains the zone of overlap, the region where we find thick and thin filaments and where tension is generated during contraction

A

A bands

50
Q

In the middle of the A band where only thick filaments exist is

A

H zone

51
Q

is found in the middle of the I band and is composed of structural proteins that:

  • Anchor the thin filaments in place and to one another
  • Serve as attachment points for elastic filaments
  • Attach myofibrils to one another across the entire diameter of the muscle fiber
A

Z disc

52
Q

explains how tension is generated during muscle contraction

A

the sliding-filament mechanism

53
Q

due to an unequal distribution of ions near the plasma membrane resulting in a polarized resting state

A

membrane potentials

54
Q

When the barrier separating the ions is removed, they follow their gradients, creating a flow of electrical charges, and the potential energy becomes

A

kinetic energy

55
Q

the electrical potential across the sarcolemma of a resting muscle fiber and it measures 85 mV, meaning the cytosol is 85 mV more negative than the extracellular fluid

A

the resting membrane potential

56
Q

can then move through the sarcolemma using protein channels and carriers

A

sodium and potassium ions

57
Q

how is the concentration gradient maintained?

A

the Na+/K+ pump

58
Q

how many sodium ions and potassium ions does the pump move?

A

3 sodium ions out of the cell and 2 potassium ions into the cell

59
Q

brief changes in the membrane potential of a cell from a resting negative value to a positive value, then back to its resting negative value

A

action potentials

60
Q

open in response to the presence of a chemical

A

ligand-gated channels

61
Q

open and close in response to changes in the membrane potential of the plasma membrane

A

voltage gated channels

62
Q

begins when voltage-gated Na+ channels open, allowing Na+ to flow inward

A

depolarization

63
Q

begins after Na+ channels have closed and voltage-gated K+ channels have opened, allowing K+ to diffuse out of the cell

A

repolarization

64
Q
  • the synapse where a single motor neuron communicates with many muscle fibers
  • function is to transmit a signal, called a nerve impulse (an action potential), from the neuron to the sarcolemma of the muscle fiber
A

The neuromuscular junction

65
Q

are chemicals that trigger changes in a target tissue when released, allowing for cell to cell communication

A

neurotransmitter

66
Q

the space between axon terminal and muscle fiber, filled with collagen fibers and a gel that anchors the neuron in place

A

synaptic cleft

67
Q

specialized region of the muscle fiber plasma membrane whose folded surface has many ligand-gated Na+ channels; ACh is the ligand that opens these gates, allowing Na+ to diffuse into the muscle cell

A

motor end plate

68
Q

begins when an action potential signals the release of acetylcholine from the axon terminal into the synaptic cleft

A

excitation phase

69
Q

the link between the stimulus and the contraction

A

excitation-contraction coupling

70
Q

begins when Ca++ ions bind troponin, which pulls tropomyosin away from actin’s active site; the crossbridge cycle then begins

A

contraction phase

71
Q

diffuses across the synaptic cleft where it can bind to ligand-gated channels found in the motor end plate of the muscle fiber sarcolemma

A

acetylcholine

72
Q

Ligand-gated channels open when they bind acetylcholine which allows Na+ ions to enter the muscle fiber generating an

A

end plate potential

73
Q

Motor neurons continue to fire action potentials as acetylcholine is rapidly degraded by the enzyme

A

acetylcholinesterase

74
Q

The end plate potential is generated by the influx of _______ into the motor end plate.

A

sodium

75
Q

Acetylcholine is released from the synaptic terminus in response to

A

An action potential arriving at the synaptic terminus

76
Q

The term “synaptic cleft” refers to

A

The gap between the neuron and the muscle fiber

77
Q

The sodium channels of the motor end plate are

A

ligand-gated channels

78
Q

The end plate potential is

A

a local depolarization

79
Q

leads to the opening of VOLTAGE-gated Na+ channels in the sarcolemma surrounding the motor end plate, which triggers an action potential

A

end-plate potential

80
Q

The channels that open in the sarcolemma surrounding the motor endplate and generate an action potential are

A

voltage-gated channels

81
Q

The term “propagate” when referring to an action potential means

A

spread

82
Q

In order to trigger a muscle contraction, an action potential must reach the

A

triads

83
Q

a triad consist of

A

Two terminal cisternae and a T-tubule

84
Q

________ is released from the SR in response to arrival of an action potential

A

Ca2+

85
Q

Covers actin active sites

A

tropomyosin

86
Q

Troponin has three subunits. Which of the following does NOT bind to one of these subunits?

A

myosin

87
Q

Action potential arrives at triad, calcium is released from the terminal cisternae, calcium binds to troponin, tropomyosin exposes the actin active sites

A

sequence of events that occur in preparation for contraction

88
Q

begins when actin’s active site is exposed, initiating the crossbridge cycle

A

contraction phase

89
Q

occurs when ADP + Pi are released from the myosin head

A

power stroke

90
Q

Hydrolysis of ATP is responsible for

A

Recocking of the myosin heads

91
Q

The binding of ATP to myosin is responsible for

A

Release of the myosin heads from the actin active sites

92
Q

The release of ADP and Pi from myosin occurs during

A

the power stroke

93
Q

The myosin heads return to their low-energy (relaxed) state during

A

the power stroke

94
Q

Pulls the thin filaments toward the M lines

A

the power stroke

95
Q

During muscle fiber relaxation, calcium channels in the SR close because

A

The resting membrane potential is restored

96
Q

During muscle fiber relaxation

A

Calcium is pumped back into the SR

97
Q

Acetylcholinesterase in the synaptic cleft degrades acetylcholine, allowing

A

Ligand-gated sodium channels to close

98
Q

Sarcolemma repolarization during relaxation

A

Restores the resting membrane potential

99
Q

Which aspect of muscle relaxation requires ATP?

A

Pumping calcium ions back into the SR

100
Q

concentration in the cytosol is 5–6 times higher than ATP; it can immediately regenerate enough ATP for about 10 seconds of maximum muscle activity

A

creatine phosphate

Final Lab & Lecture Exam (3 decks)

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