Chapter 6: The Muscular System Flashcards

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1
Q

What are the 3 types of muscles?

A

Skeletal Muscle
Cardiac Muscle
Smooth Muscle

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2
Q

What is the location of skeletal muscle?

A

Attached to bone or skin (for some facial muscles)

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3
Q

What is the location of cardiac muscle?

A

walls of the heart

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4
Q

What is the location of smooth muscle?

A

mostly in walls of visceral organs (other than the heart)

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5
Q

What do skeletal muscle cells look like ?

A

Single, very long, cylindrical, multinucleate cells with very obvious striations

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6
Q

What do cardiac muscle cells look like ?

A

branching chains of cells, uninucleate, striations, intercalated discs

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7
Q

What do smooth muscle cells look like ?

A

single, fusiform, uninucleate, no striations

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8
Q

What are the connective tissue components of skeletal muscle?

A

Endomysium, perimysium, and epimysium

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9
Q

What are the connective tissue components of cardiac muscle?

A

endomysium

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10
Q

What are the connective tissue components of smooth muscle?

A

endomysium

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11
Q

Endomysium

A

encloses a single muscle fiber

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12
Q

perimysium

A

wraps around a fascicle (bundle) of muscles fibers

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13
Q

Epimysium

A

covers the entire skeletal muscle

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14
Q

fascia

A

on the outside of the epimysium

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15
Q

What is the direct attachment from muscle to bone?

A

epimysium

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16
Q

What are 2 indirect attachments from muscle to bones?

A

tendon and aponeurosis

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17
Q

Name the descending order of size muscle structures.

A
Muscle
Muscle fascicle
Muscle fiber (AKA muscle cell) 
Myofibril
myofilaments = actin & myosin
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18
Q

Tendon

A

cord-like structures
mostly collagen fibers
often cross a joint due to toughness and small size

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19
Q

aponeuroses

A

sheet-like structures

attach muscles indirectly to bones, cartilages, or connective tissue coverings

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20
Q

skeletal muscle attachement sites

A

bones
cartilages
connective tissue coverings

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21
Q

skeletal muscle functions (4)

A

produce movement, maintain posture, stabilize joints, generate heat

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22
Q

sacrolemma

A

specialized plasma membrane

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23
Q

myofibrils

A

long organelles inside muscle cell

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24
Q

sacroplasmic reticulum

A

specialized smooth endoplasmic reticulum

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25
Q

What are the bands of myofibrils?

A

I band - light band, contains only thin filaments

A band = dark band, contains the entire length of the thick filaments

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26
Q

sacromere

A

contractile unit of a muscle fiber

contains myofilaments

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27
Q

Myofilaments

A

thick filaments = myosin filaments

thin filaments = actin filaments

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28
Q

thick filaments

A

myosin filaments
composed of the protein myosin, has ATPase enzymes, myosin filaments have heads (extensions, or cross bridges), myosin and actin overlap somewhat

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29
Q

Thin filaments

A

actin filaments

Composed of the protein actin, anchored to the Z disc

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30
Q

What kind of filaments are in the A band.

A

It has myosin, and lacks actin filaments

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31
Q

sacroplasmic reticulum

A

stores and releases calcium

surrounds the myofibril

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32
Q

excitability

A

aka responsiveness or irritability

ability to receive and respond to a stimulus

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33
Q

contractility

A

ability to shorten when an adequate stimulus is received

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34
Q

extensibility

A

ability of muscles cells to be stretched

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35
Q

elasticity

A

ability to recoil and resume resting length after stretching

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36
Q

motor unit

A

one motor neuron and all the skeletal muscle cells stimulated by that neuron

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37
Q

neuromuscular junction

A

association site of axon terminal of the motor neuron and muscle

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38
Q

synaptic cleft

A

gap between nerve and muscle
nerve and muscle do not make contact
area between nerve and muscle is filled with interstitial fluid

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39
Q

Describe the nerve stimulus and action potential

A

The stimulus goes to the synaptic cleft and the action potential reaches the axon terminal of the motor neuron. The Calcium channels open and calcium ions enter the axon terminal.

40
Q

Describe the transmission of nerve impulse to muscle

A

calcium ion entry causes some synaptic vesicles to release their contents (acetylcholine, a neurotransmitter) by exocytosis. ACh attaches to receptors on the sarcolemma of the muscle cell. The sarcolemma becomes permeable to Na+. Na+ rushes into the cell generating an action potential and potassium leaves the cell. Once started, muscle contraction cannot be stopped.

41
Q

neurotransmitter

A

chemical released by nerve upon arrival of nerve impulse in the axon terminal.

42
Q

What’s the neurotransmitter for skeletal muscle?

A

acetylcholine (ACh)

43
Q

Describe the Sliding Filament Theory of Muscle Contraction

A

Activation by nerve causes myosin heads (cross bridges) to attach to binding sites on the thin filament. Myosin heads then bind to the next site of the thin filament. Myosin heads then bind to the next site of the thin filament and pull them toward the center of the sarcomere. This continued action causes a sliding of the myosin along the actin. THe result is that the muscle is shortened (contracted)

44
Q

graded responses

A

different degrees of skeletal muscle shortening

Changes based on the frequency of muscle stimulation and the number of muscle cells being stimulated at one time.

45
Q

Twitch

A

single, brief contraction

Not a normal muscle function

46
Q

Summing of contractions

A

one contraction immediately followed by another.
The muscle does not completely return to a resting state due to more frequent stimulations
The effects are added.

47
Q

Unfused (incomplete) tetanus

A

Some relaxation occurs between contractions but nerve stimuli arrive at an even faster rate than during summing of contractions. Unless the mucles contraction is smooth and sustained, it is said to be unfused tennis,.

48
Q

Fused (complete) tetanus

A

No evidence of relaxation before the following. Frequency of stimulations does not allow for relaxation between contractions.
The result is a smooth and sustained muscle contraction.

49
Q

What is the first source of energy for muscle contraction?

A

ATP. It is stored in the muslces.

only provides 4-6 seconds worth of energy stored by muscles.

50
Q

What is the second source of energy for muscle contraction?

A

Direct phosphorylation of ADP by creatine phosphate (CP). Muscle cells store CP. CP supplies are exhausted in less than 15 seconds. About 1 ATP is created per CP molecule.
CP transfers a phosphate group to ADP to regenerate ATP.

51
Q

Aerobic respiration

A

Glucose is broken down to carbon dioxide and water, releasing energy (about 32 ATP).
A series of metabolic pathways occur in the mitochondria.
This is a slower reaction that requires continuous oxygen.
Carbon dioxide and water are produced.

52
Q

Anaerobic glycolysis and lactic acid formation

A

reaction that breaks down glucose without oxygen.
GLucose is broken down to pyretic acid to produce about 2 ATP.
Pyruvic acid is converted to lactic acid.
This is fast, but inefficient.
Lactiv acid produces muscle fatigue.

53
Q

oxygen deficit

A

A common cause of muscle fatigue. Must be “repaid” to cure muscle fatigue. Oxygen is required to rid of accumated lactic acid.

54
Q

Isotonic contractions

A

The muscle shortens and movement occurs . Myofilaments are able to slide past each other during contractions.

55
Q

Isometric contractions

A

Tension in the muscles increases. The muscle is unable to shorten or produce movement.

56
Q

Muscle Tone

A

some fibers are contracted even in a relaxed muscles. Different fibers contract at different times to provide muscle tone and to be constantly ready.

57
Q

Five Golden Rules of Skeletal Muscle Activity

A
  1. With a few exceptions, all skeletal m muscles cross at least one joint.
  2. Typically, the bulk of a skeletal muscle lies proximal to the joint crossed.
  3. All skeletal muscles have at least tow attachments; the origin and the insertion.
  4. Skeletal muscles can only pull; they never push
  5. During contraction, a skeletal muscle insertion moves toward the origin.
58
Q

The origin is attachment to a __________ bone

A

movable

59
Q

The insertion is the attachment to an __________ immovable bone.

A

immovable

60
Q

Inversion

A

turn sole of foot medially

61
Q

Eversion

A

turn sole of foot laterally

62
Q

Frontalis

A

raises eyebrows

63
Q

orbicularis oculi

A

closes eyes, squints, blinks, winks

64
Q

buccinator

A

flattens the cheek, chews

65
Q

zygomaticus

A

raises corners of the mouth

66
Q

messeter

A

closes the jaw and elevates the mandible

67
Q

Temporalis

A

synergist of the masseter, closes jaw

68
Q

platysma

A

pulls the corners of the mouth inferiorly

69
Q

sternocleidomastoid

A

flexes the neck, rotates the head

70
Q

pectoralis major

A

adducts and flexes the humerus

71
Q

intercostal muscles:
External intercostals
Internal intercostals

A

external: raise rib cage during inhalation
Internal: depress the rib cage to move air out of the lungs when you exhale forcibly

72
Q

rectus abdominis

A

flexes the vertebral column and compresses abdominal contents (defecation, childbirth, forced breathing)

73
Q

external oblique

A

flex vertebral column, rotate trunk and bed it laterally

74
Q

internal oblique

A

flex vertebral column, rotate trunk and bend it laterally

75
Q

transversus abdominis

A

compresses abdominal contents

76
Q

Trapezius

A

elevates, depresses, adducts, and stabilizes the scapula

77
Q

latissimus dorsi

A

extends and adducts the humerus

78
Q

erector spinae

A

beck extension

79
Q

quadratus lumborum

A

flexes the spine laterally

80
Q

deltoid

A

arm abduction

81
Q

Erector Spinae

I LOVE SPINES (3)

A

Iliocostalis
Logissimus
Spinalis

82
Q

biceps brachii

A

supinates forearm, flexes elbow

83
Q

brachialis

A

elbow flextion

84
Q

brachiradialis

A

weak muscle; elbow flexion

85
Q

Triceps brachii

A

elbow extension (antagonist to biceps brachii)

86
Q

gluteus maximus

A

hip extension

87
Q

gluteus medius

A

hip abduction, steadies pelvis when walking

88
Q

iliopsoas

A

hip flexion, keeps the upper body from falling backward when standing erect

89
Q

adductor muscles

A

adduct the thighs

90
Q

Hamstring group (3) = thigh extension and knee flexion

A

biceps femoris
semimembranosus
semitendinosus

91
Q

sartorius

A

flexes the thigh

92
Q

quadriceps group (2) = extends the knee

A
rectus femoris
vastus muscles (3)
93
Q

Tibialis anterior

A

dorsiflextion, floot inversion

94
Q

extensor digitorum longus

A

toe extension and dorsiflextion of the foot

95
Q

fibularis muscles

A

plantar flexion, foot eversion

96
Q

soleus

A

plantar flexion

97
Q

gastrocnemius

A

plantar flexion