Muscular System Flashcards

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0
Q

Smooth Muscle

A

Narrow cylindrical fibers, non-striated, uninucleate; occurs in walls of internal organs; is involuntary;

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1
Q

Types of Muscle

A

Smooth Muscle
Cardiac Muscle
Skeletal Muscle

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2
Q

Cardiac Muscle

A

Has striated, branched, generally uninucleated fibers; occurs in walls of heart; is involuntary;

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3
Q

Skeletal Muscle

A

Has striated, tubular, multinucleated fibers; is usually attached to skeleton; is voluntary.

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4
Q

Functions of the Muscular System

A

Support the body
Allow for movement of bones and other structures
Help maintain constant body temperature
Assist in movement of fluids in cardiovascular and lymphatic vessels
Protect

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5
Q

Bursa

A

Fluid filled sacs that provide cushioning between tendons and bones

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6
Q

Tendon

A

The connective tissue that connects muscle to bone

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7
Q

Origin

A

Attachment of a muscle to a stationary bone

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8
Q

Insertion

A

Attachment of a muscle on a bone that moves

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9
Q

Prime Mover

A

Does most of the work when moving

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10
Q

Synergist

A

Assists the prime mover

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11
Q

Antagonist

A

Works against the prime mover - purpose is to undo what was done by the prime mover

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12
Q

Muscles are named based on what seven characteristics?

A
Size
Shape
Location
Direction of fibers
Attachment
Number of attachments
Action
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13
Q

Do muscles pull or push?

A

Pull

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14
Q

T-tubule (transverse)

A

Portion of sarcolemma that penetrates muscle cells.

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15
Q

Sarcoplasmic Reticulum

A

Smooth endoplasmic reticulum that stores Ca+

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16
Q

Sarcolemma

A

Plasma membrane

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17
Q

Sarcoplasm

A

Cytoplasm

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18
Q

Sarcomere

A

One contracting unit of the muscle cell; made of the proteins actin and myosin

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19
Q

Actin

A

thin filaments

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20
Q

Myosin

A

Thick filaments shaped like a golf club

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21
Q

I Band

A

Region on a sarcomere where actin but no myosin is

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22
Q

H zone

A

Region where myosin is but no actin

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23
Q

A band

A

Length of the myosin fiber

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24
Q

How do filaments go over one another during muscle contraction?

A

Filaments slide over one another - do NOT crunch up!

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25
Q

First step of ATP in cellular work of motion…

A

ATP is split when myosin head is unattached (so becomes ADP)

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26
Q

Second step of ATP in cellular work of motion

A

ADP + P are bound to myosin as myosin head attaches to actin

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27
Q

Third step of ATP in cellular work of motion

A

Upon ADP+P release, power stroke occurs; head bends and pulls actin

28
Q

Fourth step of ATP in cellular work of motion

A

Binding of fresh ATP causes myosin head to return to resting position

29
Q

Power Stroke

A

Movement of myosin head to pull actin

30
Q

Troponin

A

Calcium complex that modifies the position of tropomyosin

31
Q

First step of Muscle Fiber Contraction

A

Nerve impulses (action potential) travels down motor neurons to a neuromuscular junction

32
Q

Neuromuscular Junction

A

Where a motor neuron connects to skeletal muscle

33
Q

Motor unit

A

A nerve fiber and all of the muscle fibers that it innervates

34
Q

Second Step of Muscle Fiber Contraction

A

Acetylcholine (ACh) is released from the neurons and bind to the muscle fibers. (Synaptic vesicles of the neuron contain ACh, a neurotransmitter, where it binds with receptor on the sarcolemma)

35
Q

Third Step of Muscle Fiber Contraction

A

Binding of ACh stimulates impulses down the T-tibules causing calcium to be released from the sarcoplasmic reticulum

36
Q

Fourth Step of Muscle Fiber Contraction

A

Calcium complex (troponin) modifies tropomyosin, exposing binding site

37
Q

Fifth Step of Muscle Fiber Contraction

A

Myosin head binds with actin (thanks to ADP + P)

38
Q

Sixth Step of Muscle Fiber Contraction

A

ADP + P are released, resulting in a power stroke

39
Q

Seventh Step of Muscle Fiber Contraction

A

Additional ATP allows for myosin head to return to resting position and calcium to be pumped back into sarcoplasmic reticulum

40
Q

Electromyogram (EMG)

A

Method of detecting changes in ions associated with muscle contraction

41
Q

Electrical voltages

A

Difference in charge from place to place - can be detected on surface of skin

42
Q

Motor unit

A

A nerve fiber and all of the muscle fibers it stimulates - “all or none”

43
Q

Motor Unit Recruitment

A

Increases the strength of contraction by increasing the number of motor units in use

44
Q

Fatigue sets in when…

A

…you have recruited same motor units for a while and depleted energy (ATP)

45
Q

Muscle twitch is…

A

A single motor unit contraction, caused by infrequent electrical impulses, and lasts a fraction of a second.

46
Q

Summation

A

Increase in muscle contraction until maximum sustained contraction (tetanus) is reached, and lasts until fatigue (muscle relaxes despite stimulation due to depletion of energy reserves).

47
Q

Tetanus

A

Maximal sustained contraction

48
Q

Fatigue

A

Decrease in a muscle’s ability to generate force, when the muscle relaxes despite stimulation due to depletion of energy reserves.

49
Q

Four sources of ATP for muscle contraction…

A

Stored in muscle fibers
Creatine-phosphate pathway
Fermentation
Cellular Respiration

50
Q

Creatine-phosphate pathway

A

Fastest way to acquire ATP but only sustains cell for seconds; builds up when a muscle is resting (anaerobic).

51
Q

Fermentation

A

Fast-acting but results in lactate build-up (anaerobic)

52
Q

Cellular Respiration

A

Not an immediate source of ATP, but best long term source (aerobic)

53
Q

Myoglobin

A

Protein that transports oxygen directly to mitochondria of muscle cells

54
Q

Fast Twitch Fiber Characteristics

A
Creatine-Phosphate pathway and fermentation for ATP
Fewer Mitochondria
Light Color 
Fewer blood vessels
Little myoglobin
55
Q

Slow Twitch Fiber Characteristics

A
Cellular Respiration for ATP
More mitochondria
Dark color 
More blood vessels
More myoglobin
56
Q

Fast Twitch Muscle Characteristics

A

Anaerobic
Explosive Power
Fatigues Easily

57
Q

Slow Twitch Muscle Characteristics

A

Is Aerobic
Steady Power
Has Endurance

58
Q

Spasms

A

Sudden, involuntary muscle contractions that are usually painful

59
Q

Seizure/Convulsion

A

Multiple spasms of skeletal muscles

60
Q

Cramps

A

Strong, painful spasms often of the leg and foot

61
Q

Strain

A

Stretching or tearing of a muscle

62
Q

Sprain

A

Twisting of a joint involving muscle, ligaments, and joints

63
Q

Fibromyalgia

A

Chronic achy muscles; not well understood

64
Q

Muscular Dystrophy

A

Group of genetic disorders in which muscles progressively degenerate and weaken

65
Q

Myasthenia Gravis

A

Autoimmune disorder that attacks ACh receptors and weakens muscles of the face, neck, and extremities

66
Q

Muscle Cancer

A

Cancers originating in support tissues (bone, muscle) are called sarcoma

67
Q

Amyotrophic Lateral Sclerosis (ALS)

A

Lou Gehrig’s Disease; genetic disorder in which motor neurons degenerate leading to loss of voluntary muscle contractions

68
Q

Muscles contribute to homeostasis how…?

A

Allow for movement to let us respond to stimuli, digest food, breathe, etc.
Protect body parts
Helps to regulate body temperature