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APHY 165 > AnP Chapter 10 (LO8) > Flashcards

AnP Chapter 10 (LO8) Flashcards

1
Q

Body contains over ——muscles which comprise about –% of adults weight

A

Body contains over 600 muscles which comprise about 40% of adults weight

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2
Q

3 TYPES OF MUSCLES

A

Cardiac muscle

Smooth muscle

Skeletal muscle

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3
Q

Cardiac muscle

A

Found only in heart

Consists of short, branching fibers that fit together at intercalated discs

Striated

Is a type of involuntary muscle because it contracts automatically

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4
Q

Smooth muscle

A

Found in digestive tract, blood vessels, bladder, airways and uterus

Nonstriated

Involuntary muscle

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5
Q

Skeletal muscle

A

Attached to bone and causes movement of the body

Voluntary: contracted at will

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6
Q

SKELETAL MUSCLE STRUCTURE

A

Consists of bundles of tiny fibers that run the length of muscle

Most fibers are about 3cm long and 0.05mm wide

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7
Q

Endomysium

A

delicate connective tissue that covers each muscle

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8
Q

Fascicles

A

muscle fibers grouped in bundles

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9
Q

Perimysium

A

a sheath of tougher connective tissue that encases fascicles

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10
Q

Epimysium

A

layer of connective tissue that surrounds and binds all the muscle fiber together

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11
Q

Fascia

A

connective tissue that surrounds the muscle outside the epimysium

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12
Q

Deep fascia

A

lies between muscles

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13
Q

Superficial fascia

A

resides just underneath the skin

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14
Q

Skeletal may attach to bone in 1 of 2 ways

A

Direct attachment

Indirect attachment

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15
Q

Direct attachment

Indirect attachment

A

Direct attachment: muscle fibers merge with the periosteum of the bone forming a strong attachment

Indirect attachment: the epimysium extends past the muscle as a tendon

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16
Q

STRUCTURE OF MUSCLE FIBERS

A

Muscle cells are called muscle fibers because they’re long, thread like

Have multiple nuclei pressed against the side of the plasma membrane

Complex interior

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17
Q

Sarcolemma

A

the plasma membrane surrounding each fiber

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18
Q

Sarcoplasm

A

cytoplasm of the cell

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19
Q

Myofibrils

A

long protein bundles that fill the sarcoplasm

Store glycogen (used for energy) and 02

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20
Q

Sarcoplasmic reticulum (SR)

A

smooth endoplasmic reticulum of a muscle fiber

Surrounds each myofibril

Where calcium ions are stored

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21
Q

Myofilaments:

A

2 types thick and thin

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22
Q

Myosin

actin

A

Myosin: protein that makes up thick myofilaments

Actin: protein that makes up thin myofilaments

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23
Q

Transverse tubules

A

extend across the sarcoplasm

Formed from inward projections of the sarcolemma

Allow electrical impulses to travel deep into the cell

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24
Q

THICK FILAMENTS

A

Consists of hundreds of myosin molecules stacked together

Myosin head faces outward

Myosin molecule is shaped like a golf club

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25
Q

THIN FILAMENTS

A

Consist of 2 chains of actin

Look like string of beads

actin

tropomyosin and troponin

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26
Q

Actin

tropomyosin and troponin

A

Actin: contractile protein

Tropomyosin and troponin: proteins entwined with actin

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27
Q

STRUCTURE OF MYOFIBRIL

A

Thick and thin myofilaments stack together to form myofibrils

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28
Q

Sarcomere

A

units of contraction of the myofilaments of a muscle

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29
Q

Z-disc/z-line

A

a plate/disc that serves as an anchor point for thin myofilaments

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30
Q

cross-bridge

A

when myosin attaches to actin

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31
Q

*contraction occurs when…

A

*contraction occurs when the myosin head latches onto actin

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32
Q

Motor neuron

A

a nerve that can stimulate skeletal muscle to contract

Found in brainstem and spinal cord

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33
Q

Axons

A

carry impulses to skeletal muscles

Each branch stimulated a different muscle fiber

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34
Q

Neuromuscular junction

A

connection between motor neuron and a muscle fibre

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35
Q

Synaptic cleft

A

between end of the motor nerve and the muscle fiber

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36
Q

HOW MUSCLE FIBERS CONTRACT

A
  1. When an impulse reaches end of motor neuron and neurotransmitter is released acetylcholine (Ach) the neurotransmitter released into the synaptic cleft
  2. Ach stimulates receptors in the sarcolemma: membrane surrounding muscle fiber
  3. Electrical impulses sent over the sarcolemma along T tubules
    - –T tubules cause the sacs in the sarcoplasmic reticulum to release calcium
  4. The calcium binds with the troponin to expose attachment points on actin
    - –The myosin heads of thick grab the thin and muscle contraction occurs
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37
Q

HOW MUSCLE FIBERS RELAX

A
  1. Ach is no longer released when nerve impulses stop arriving at the neuromuscular junction
  2. Acetylcholine esterase: breaks down remaining Ach
  3. Calcium ions are pumped back into the sarcoplasmic reticulum
  4. Troponin and tropomyosin prevent the myosin head from grasping the thin filament
  5. Muscle relaxes
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38
Q

Myasthenia

A

body produces antibodies against receptors for Ach nerve transmission is poor and profound muscular weakness

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39
Q

Tetanus

A

“lock jaw” bacteria which causes motor neurons to fire excessively leads to overstimulation of muscles resulting in severe muscle spasms

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40
Q

how MUSCLE TONE works

A
  1. Sarcomeres are shortened in overly contracted fibers
    - -Fibers can’t contract very for before thick filaments bump into z-discs
    - -Contractions are weak
  2. An overly stretched fibers thin filaments have little overlap
    - -Only small part of thin filament accessible for myosin heads to grab
    - -Contractions are weak
  3. When thin and thick filaments partially overlap contractions are strong
    - -Z-discs are far enough apart to allow for movement during contraction
    - -Thin/thick filaments overlap enough to allow the myosin head to grip the thin actin filaments
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41
Q

Muscle tone

A

continuous state of partial contraction

Allows you to stand, hold head up and maintain posture

Allows you to react quickly to a dangerous situation

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42
Q

Motor unit

A

one motor neuron and all the fibers (group) it stimulates

A single motor can consist of a few fibers or hundreds

These fibers are scattered throughout the muscle rather than bunched this allows contraction to be spread over wide area

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43
Q

Threshold

A

minimum voltage needed to cause a muscle fiber to contract

44
Q

Twitch

A

brief contraction when a fiber receives a stimulus at or above threshold

45
Q

Force of contraction is affected by a number of things including

A

size of muscle, the degree of stretch and number of muscle fibers contracting

46
Q

Nervous system responds to demands placed on muscles in 2 ways

A

Altering the frequency of the stimulus

Altering the intensity of the stimulus

47
Q

how Stimulus frequency works

A
  1. Frequency of stimuli can alter contraction strength
  2. The last contraction will be stronger than the first when a muscle contracts several times in a row
  3. Sarcoplasmic reticulum doesn’t have time to completely reabsorb calcium ions
  4. Increased calcium = more forceful contraction
48
Q

Treppe

A

phenomenon that each successive twitch contracts more forcefully than previous

49
Q

Incomplete tetanus

A

condition of rapid contraction with only partial relaxation

50
Q

Complete tetanus

A

impulses arrive so fast that the muscles can’t relax at all between stimuli

51
Q

Strong stimulus

A

May stimulate all the fibers in a motor nerve

Nerve fibers call on muscle fibers to contract (more fibers contracting= stronger)

Recruitment: the process by which an increasing number of motor units are called into action

52
Q

Weak stimulus

A

Just a few nerve fibers

May stimulate just one nerve fiber and the muscle fibers connected

Fewer fibers= weaker

53
Q

Isotonic contractions

A

muscle contraction that shortens the muscle 

Ex)lift barbell 

54
Q

Isometric contractions

A

muscles contract by increasing tension while the length stays the same 

Ex) pulling on cable fastened to a stationary object 

55
Q

At rest energy is obtained by…

A

metabolizing fatty acids

56
Q

Aerobic respiration

A

used to break down fatty acids for energy

57
Q

Creatine phosphate (CP):

A

compound stored in muscle and broken down when muscles restock their supply of ATP

Can furnish the muscle with fuel for 20 secs high activity or 1 minute of moderate activity

58
Q

Anerobic respiration

A

use of glucose when CP runs out before oxygen has reached an acceptable level

Can generate energy quickly and is useful for intense bursts of activity

59
Q

Lactic acid:

A

produced by-product from anerobic respiration which accumulates in muscle and leads to muscle fatigue

60
Q

After about 10mins of moderate activity heart and lungs increase oxygen to muscles…

A

Muscles shift back to aerobic respiration which produces c02 and water rather than lactic acid

61
Q

Origin

A

refers to the end of the muscle that attaches to the more stationary bone

Ex) origin of biceps is the scapula which is relatively immobile

62
Q

Belly

A

the thick midsection of the muscle

63
Q

Insertion

A

the end of the muscle that attaches to the movable bone

Ex) insertion of biceps is the radius muscle pulls the radius towards the scapula

64
Q

Prime mover

A

main muscle triggering the movement

65
Q

Synergists

A

the muscles that assist the prime mover

66
Q

Antagonist

A

muscles balancing the movements by opposing the action of prime mover

When prime mover contacts antagonist relax and give prime mover control

67
Q

Hypertrophy

A

strength training causing muscles to enlarge

Intense exercise slightly injure fibers as the body repairs the fibers enlarge

68
Q

Atrophy

A

lack of use causes the muscle fibers and entire muscle to shrink

Endurance exercise stimulates the growth of blood vessels in muscles allowing increase supply of 02 and glucose necessary for ATP

69
Q

Frontalis

A

raises eyebrows when glancing upwards or showing surprise

70
Q

Orbicularis oculi

A

a sphincter muscle that closes the ye when blinking or squinting

71
Q

Zygomaticus

A

draws the mouth upward when laughing

72
Q

Orbicularis oris

A

closes the mouth and purses the lips ex kissing

73
Q

Buccinator

A

assists in smiling, blowing and chewing

74
Q

Temporalis

A

aids in closing jaw

75
Q

Masseter

A

closes jaw

76
Q

Sternocleidomastoid

A

flexes the head, rotates head opposite side only one muscle contracts

77
Q

Trapezius

A

extends head also elevates shoulder

78
Q

External intercostals

A

lie superficially between ribs; elevate ribs during inspiration

79
Q

Diaphragm

A

enlarges the thorax to trigger inspiration

80
Q

External oblique

A

compresses the abdominal organs which aids in forcefull expiration, vomiting, and defecation also allows flexion of vertebral column and rotation and lateral bending of trunk

run in a Downward and anterior direction

81
Q

Rectus abdominis

A

flexes the lumbar region of the spinal column to cause bending forward at the waist; extends from sternum to pubic bone

82
Q

Transverse abdominis

A

compresses the contents of the abdomen

runs in a Horizontal direction

83
Q

Internal oblique

A

stabilizes the spine and maintains posture, also permits rotation of waist

runs in a Upward and anterio direction

84
Q

Deltoid

A

abducts, flexes, rotates the arm; involved in swinging the arm; raises arms

85
Q

Pectoralis major

A

flexes and adducts the upper arm, such as when climbing or hugging

86
Q

Trapezius

A

raises and lowers shoulders; stabilizes scapula during arm movements

87
Q

Latissimus dorsi

A

adducts the humerus; extends upper arm backwards; pull the body upward when grasping an object overhead

88
Q

Rotator cuff

A 
tendons of 4 muscles form rotator cuff 
Supraspinatus 
Infraspinatus 
Teres minor 
Subscapularis
89
Q

Brachialis

A

the prime mover when flexing the forearm

90
Q

Biceps brachii

A

assists the brachialis when flexing the forearm; also flexes elbow and supinates the forearm

91
Q

Triceps brachii

A

the prime mover when extending the forearm

92
Q

Brachioradialis

A

helps the brachialis and the biceps brachii flex the forearm

93
Q

Pronator muscle

Supinator muscle

A

Pronator muscle: allow the arm to pronate

Supinator muscle: lies deep in forearm near elbow allows supination

94
Q

Flexor

Extensor

A

Flexor: muscles that flex wrist; located on anterior of forearm

Extensors: muscles that extend the wrist; located on posterior of forearm

95
Q

Iliopsoas

A

flexes the thigh

Illiacus

Psoas major

96
Q

Sartorius

A

longest muscle in body; aids in flexion of hip and knee; abducts and laterally rotates the thigh

97
Q

Adductor muscles

A

rotate and draw the thigh in toward the body consists of

Adductor magnus

Adductor brevis

Adductor longus
Gracilis

98
Q

Quadriceps femoris

A

the most powerful muscle in the body; prime mover for knee extensions consists of

4 muscles: 
Vastus intermedius 
Rectus femoris 
Vastus lateralis 
Vastus medialis
99
Q

Gluteus Medius

A

abducts and rotates the thigh outward

100
Q

Gluteus maximus

A

the bulkiest muscle in the body; produces backswing of leg when walking and provides power for climbing stairs

101
Q

Gluteus minimus

A

this muscle lies beneath the other two; it assists the gluteus Medius in abducting when leg is extended; aids in internally/externally rotating thigh

102
Q

Hamstrings

A

group of muscles consisting of following 3:
Biceps femoris
Semitendinosus
Semimembranosus

All work to extend thigh at hip, flex knee, and rotate leg

103
Q

Calf is 2 muscles:

A

Gastrocnemius (more superficial)

Soleus (deeper)

104
Q

Calcaneal (Achilles) tendon

A

tendon of the gastrocnemius

105
Q

Extensor digitorum longus

A

extends toes and turns foot outward

106
Q

Tibialis anterior

A

keep toes from dragging on floor

APHY 165 (12 decks)

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