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Anatomy & Physiology 1 > Chapter 9 > Flashcards

Chapter 9 Flashcards

1
Q

Muscle tissue is specialized for _____.

A

muscle contraction

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2
Q

Three types of muscle tissue

A

Skeletal muscle tissue
Cardiac muscle tissue
Smooth muscle tissue

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3
Q

Is skeletal muscle voluntary or involuntary?

A

voluntary

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4
Q

Is cardiac muscle voluntary or involuntary?

A

involuntary

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5
Q

Is smooth muscle voluntary or involuntary?

A

involuntary

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6
Q

Six functions of skeletal muscle tissue

A 
Produce skeletal movements
Maintain posture and body position
Support soft tissues
Guard entrances and exits
Maintain body temperature
Provide nutrient reserves
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7
Q

Dense layer of collagen fibers surrounding entire muscle

Separates muscle from surrounding tissues and organs

A

Epimysium

SKeletal muscle

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8
Q

Fibrous layer that divides muscle into bundles of fibers called muscle fascicles
Contains collagen and elastin fibers, blood vessels, and nerves

A

Perimysium

Skeletal muscle

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9
Q

Delicate connective tissue surrounding individual muscle fibers
Contains capillaries, myosatellite cells, and axons of neurons that control muscle fibers

A

Endomysium

Skeletal muscle

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10
Q

Bundle of fibers that attach muscle to bone

A

tendon

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11
Q

Sheet of fibers that attaches muscle to broader area

A

aponeurosis

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12
Q

What do skeletal muscle cells develop from?

A

myoblasts

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13
Q

Instead of fusing, a few myoblasts remain as _____ cells in endomysium and aid in muscle repair

A

myosatellite

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14
Q

Many nuclei = many genes = faster _____ production

A

protein

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15
Q

How many nuclei does a skeletal muscle cell contain?

A

hundreds

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16
Q

Skeletal muscle cell

A

muscle fiber

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17
Q

Skeletal muscle cell membrane

A

sarcolemma

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18
Q

Skeletal muscle cytoplasm

A

sarcoplasm

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19
Q

Skeletal muscle endoplasmic reticulum

A

sarcoplasmic reticulum

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20
Q

Each is banded and gives the skeletal muscle cells their banded appearance

A

myofibrils

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21
Q

Thin filaments composed mostly of _____

A

actin

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22
Q

Thick filaments composed primarily of _____

A

myosin

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23
Q

Repeating functional units of skeletal muscle fiber

A

sarcomeres

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24
Q

Thin and thick filaments interspersed

A

Zone of overlap

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25
Q

Boundary between adjacent sarcomeres

A

Z lines

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26
Q

Connects central portion of each thick filament

A

M lines

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27
Q

Darker, dense sarcomere region containing thick filaments and thin filaments
The length of the thick filament

A

A band

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28
Q

Lighter band containing only thin filaments (no thick)

Extends from A band of one sarcomere to the next A band

A

I band

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29
Q

Lighter region around M line

Contains only thick filaments (no thin)

A

H line

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30
Q

Separates sarcoplasm from interstitial fluid

A

sarcolemma

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31
Q

Changes in skeletal muscle membrane permeability cause drastic change in _____

A

electrical charge distribution

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32
Q

Encircle sarcomere and tightly bind to sarcoplasmic reticulum

A

Transverse tubules (T tubules)

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33
Q

Pair of terminal cisternae and one T-tubule form _____

A

triad

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34
Q

Tubular network around each myofibril

Forms enlarged sections (terminal cisternae) on either side of T-tubule

A

Sarcoplasmic reticulum (SR)

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35
Q

Sarcoplasmic reticulum function

A

SR contains calcium
Pumps on membrane moves calcium from cytosol to inside SR
Beginning of muscle contraction

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36
Q

Two regulatory proteins of thin filaments

A

Tropomyosis (muscle relaxed)

Troponin (muscle contracting)

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37
Q

Contain myosin molecules

A

thick filaments

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38
Q

Composed primarily of actin

A

thin filaments

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39
Q

When muscles contract, thin filaments slide past thick filaments

A

Sliding filament theory

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40
Q

In the sliding filament theory, do H bands and I bands get smaller or lager?

A

smaller

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41
Q

In the sliding filament theory, do zones of overlap get smaller or lager?

A

larger

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42
Q

In the sliding filament theory, does the width of the A band get smaller or lager?

A

remains constant

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43
Q

In the sliding filament theory, do Z lines move closer together or further apart?

A

closer together

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44
Q

All cells in the body are _____

A

polarized

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45
Q

Unequal distribution represents potential difference, referred to as _____

A

membrane potential

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46
Q

Is the inside of the cell more positive or negative than the outside of the cell?

A

negative

47
Q

Extracellular fluid contains excess ___ and ___ and the intracellular fluid contains excess ___

A

NA+
Cl-
K+

48
Q

Allow constant slow flow of sodium and potassium down their concentration gradients (Na in and K out)

A

leak channels

49
Q

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

A

Sodium–potassium ion pumps

50
Q

Changes in _____ can activate (or inactivate) voltage-gated channels that affect ion movement and distribution of electrical charges

A

membrane potential

51
Q

Five steps in action potential

A

Increase in sodium membrane permeability / MP to threshold
Voltage gated Na channels open / depolarization
Na channels close and K channels open / repolarization
K channels close / resting potential
Membrane potential stabilizes

52
Q

Time to restore levels (and during which membrane cannot respond to another stimulus)

A

refractory period

53
Q

Depolarization/repolarization sequence produces _____

A

action potential

54
Q

Function of action potential

A

allows rapid communication

55
Q

Intercellular connection between motor neuron and skeletal muscle fiber

A

Neuromuscular junction (NMJ)

56
Q

space between neuron and muscle fiber

A

synaptic cleft

57
Q

Contains vesicles filled with neurotransmitter ACh

A

Synaptic terminal of motor neuron

58
Q 
Has junctional folds (creases)
Contains acetylcholinesterase (AChE), an enzyme that breaks down ACh
A

Motor end plate of muscle fiber

59
Q

Three steps of activities at the neuromuscular junction

A 
Electrical impulse (action potential) arrives at the synaptic terminal 
ACh diffuses across synaptic cleft and binds to receptors in motor end plate
Rush of Na into sarcoplasm generates action potential on sarcolemma
60
Q

What triggers muscle contractions?

A

excitation-contraction coupling

61
Q

Three steps of excitation-contraction coupling

A 
Action potential (AP) generated at motor end plate moves across sarcolemma
Action potential moves down T tubules between terminal cisternae of SR
Calcium released from SR to sarcomeres
62
Q

Entire contraction cycle repeated as long as _____ and _____

A

Ca2+ concentrations remain high and ATP is available

63
Q

Single stimulus-contraction-relaxation sequence in a muscle fiber

A

muscle twitch

64
Q

Involuntary “muscle twitch” under skin

A

Fasciculation

65
Q

Amount of tension developed in muscle fibers shown on a _____

A

myogram

66
Q

No tension developed (contraction cycle not begun)
Action potential sweeps across sarcolemma
Calcium released from sarcoplasmic reticulum

A

latent period

67
Q

From beginning of tension development to peak tension
Calcium binds to troponin
Cross-bridge cycling occurring

A

contraction phase

68
Q

Calcium levels fall
Active sites covered by tropomyosin
Cross-bridges detach
Tension returns to resting levels

A

relaxation phase

69
Q

What is the amount of tension produced by a skeletal muscle determined by?

A

Amount of tension produced by each muscle fiber

Total number of muscle fibers stimulated

70
Q

Stimulation of skeletal muscle fiber immediately after relaxation phase produces increasing maximum tension

A

Treppe (German for staircase)

71
Q

Stimulation of skeletal muscle fiber before relaxation phase completion produces increasing maximum tension

A

wave summation

72
Q

Rapid cycle of contraction and relaxation producing almost peak tension

A

Incomplete tetanus

73
Q

Higher stimulation frequency eliminates relaxation phase and results in peak tension and continuous contraction

A

Complete tetanus

74
Q

single motor neuron and all the muscle fibers it controls

A

motor unit

75
Q

Size of motor unit varies with _____

A

muscle control

76
Q

Motor units activated on a rotating basis to maintain a sustained contraction

A

Asynchronous motor unit summation

77
Q

Smaller motor units activated first
Followed by larger, more powerful motor units with faster and more powerful fibers
Results in smooth, steady increase in muscle tension

A

recruitment

78
Q

Resting tension in a skeletal muscle

A

muscle tone

79
Q

Tension rises and skeletal muscle length changes

A

isotonic contraction

80
Q

Two types of isotonic contractions

A

Concentric contraction

Eccentric contraction

81
Q

Muscle tension rises until it exceeds load
Muscle shortens
Tension remains constant

A

Concentric contraction

82
Q

Load is more than peak tension produced

Muscle lengthens

A

Eccentric contraction

83
Q

When contraction ends, load stretches muscle until

A

Muscle tears
Tendon breaks
Elastic recoil of muscle opposes load

84
Q

Muscle length does not change

Tension never exceeds load

A

Isometric contraction

85
Q

Four sources of ATP in mucles

A

Free ATP
Creatine phosphate
Glycolysis
Aerobic metabolism

86
Q

Most energy in the muscles is stored as what?

A

Glycogen

87
Q

Occurs is sarcoplasm

Produces 2 ATP and 2 pyruvate molecules for each glucose

A

Glycolysis

88
Q

Is glycolysis aerobic or anaerobic?

A

anaerobic: does not require oxygen

89
Q

Provides 95 percent of ATP demands of resting muscle cell

Occurs in mitochondria

A

aerobic metabolism

90
Q

ATP demands increase when ____ increases

A

activity level

91
Q

What is ATP produced by?

A

mitochondria

92
Q

Glucose is converted to pyruvate. What does excess pyruvate convert to?

A

lactic acid

93
Q

When a muscle can no longer perform at the required activity level

A

fatigue

94
Q

What is a major factor in muscle fatigue?

A

decline in pH

95
Q

What happens under conditions of insufficient oxygen?

A

pH lowers
Fast ATP production
Elevated body temperature

96
Q

Intercellular conditions return to normal

A

recovery period

97
Q

Lactate produced by muscle fibers during strenuous activity

A

Lactate cycling (Cori cycle)

98
Q

Liver converts lactate to pyruvate then glucose

A

recovery period

99
Q

Lactate carried to liver by bloodstream

Liver absorbs and recycles lactate to glucose

A

Lactate cycling (Cori cycle)

100
Q

Amount of oxygen needed to return to pre-exertion conditions

A

oxygen debt

101
Q

What are the three types of skeletal muscle fibers?

A

Fast fibers
Slow fibers
Intermediate fibers

102
Q

Large in diameter
Have densely packed myofibrils, large glycogen reserves, few mitochondria
Produce powerful contractions
Fatigue rapidly because most ATP produced anaerobically

A

fast fibers

103
Q

Half diameter of fast fibers
Can maintain longer sustained contractions
Primarily use aerobic metabolism for ATP production
Increased oxygen reserves due to:
Extensive capillary network
Myoglobin pigment (stores O2 like hemoglobin)
Appear dark red from myoglobin and blood supply

A

slow fibers

104
Q

Contain little myoglobin
Relatively pale
More capillaries and more fatigue resistant than fast fibers

A

Intermediate fibers

105
Q

Hypertrophy

A

increase in muscle size

106
Q

Atrophy

A

Decrease in muscle size, tone, and power

107
Q

Inherited disease that produce muscular weakness and deterioration

A

Muscular dystrophy

108
Q

Causes progressive muscular weakness
Most individuals die from respiratory paralysis
Affects only males

A

Duchenne/Becker muscular dystrophy (DBMD)

109
Q

Virus attacks motor neurons of brain and spinal cord causing paralysis

A

Polio

110
Q

Toxin from bacteria that suppresses motor neuron activity, results in sustained, powerful contractions of affected muscles

A

tetanus

111
Q

Toxin from bacteria that blocks ACh release at neuromuscular junctions
Result is paralysis of skeletal muscle

A

Botulism

112
Q

Loss of ACh receptors at neuromuscular junctions

Results in progressive muscular weakness

A

Myasthenia gravis

113
Q

Generalized muscle contraction shortly after death

A

rigor mortis

Anatomy & Physiology 1 (5 decks)

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