Exam 2/Quiz 4- Physiology of the Muscular System Flashcards

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1
Q

Define Muscle Tension.

A

Force exerted by a contracting skeletal muscle against a load which exerts an opposing force

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2
Q

Define Motor Unit.

A

Nerve fiber + all muscle fibers it innervates

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3
Q

About how many muscles fibers per motor unit do intrinsic hand muscles have?

A

fewer than 10 muscle fibers

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4
Q

About how many muscles fibers per motor unit does the gluteus maximus muscle have?

A

100’s of muscle fibers

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5
Q

Do small specific muscles have many or less muscle fibers per motor unit? What about large muscles with general movements?

A
  1. Not many muscles fibers per motor unit

2. Many muscles fibers per motor unit

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6
Q

Define threshold stimulus.

A

Minimum stimulus strength required to initiate a contraction

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7
Q

When the threshold stimulus is reached, do the muscle fibers in a motor unit contract separately or simultaneously?

A

simultaneously

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8
Q

Graded contractions is the ability of a muscle to do what?

A

Ability of a muscle to contract in a smooth, sustained manner at various levels of strength

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9
Q

Define Tetanus.

A

sustained muscle contraction

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10
Q

What does “requirement of motor units mean”?

A

strength of the stimulus must increase to activate additional motor units

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11
Q

Does the muscle tension exceed the load (resistance), or is the muscle tension unable to overcome the load (resistance) created by the object in ISOTONIC CONTRACTION?

A

Muscle tension exceeds the load (resistance) created by the object

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12
Q

Does the muscle tension exceed the load (resistance), or is the muscle tension unable to overcome the load (resistance) created by the object in ISOMETRIC CONTRACTION?

A

Muscle tension is unable to overcome the load (resistance) created by the object

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13
Q

Do contracting muscles change in length, or do the contracting muscles not change in length in ISOTONIC CONTRACTION?

A

Contracting muscle changes in length

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14
Q

Do contracting muscles change in length, or do the contracting muscles not change in length in ISOMETRIC CONTRACTION?

A

Contracting muscles will not change in length

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15
Q

Does the object move in ISOMETRIC CONTRACTION?

A

NO

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16
Q

Although isometric contractions do not preform work, what are the important for?

A
  1. Maintaining posture

2. Stabilizing joints where movements are not desired

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17
Q

What are the two types of isotonic contractions?

A
  1. Concentric Isotonic Contraction

2. Eccentric Isotonic Contraction

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18
Q

Which type of isotonic contraction are the muscles shortening in length?

A

Concentric Isotonic Contraction

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19
Q

Which type of isotonic contraction are the muscles increasing in length?

A

Eccentric Isotonic Contraction

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20
Q

Which type of isotonic contraction do muscles preform work by moving an object from one position to another?

A

Concentric Isotonic Contraction

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21
Q

Which type of isotonic contraction do muscles not typically cause an object to be moved?

A

Eccentric Isotonic Contraction

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22
Q

What type contraction acts in coordination with other muscles that contract concentrically?

A

Eccentric Isotonic Contraction

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23
Q

Give an example of isotonic contractions regarding the anterior arm muscles:

  1. Concentric Isotonic Contraction
  2. Eccentric Isotonic Contraction
A
  1. Biceps brachii contracts concentrically

2. Triceps brachii contracts eccentrically

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24
Q

When the biceps “bulge” what type of contraction is occurring?

A

Isometric contraction

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25
Q

Which type of isotonic contraction can be said to be responsible for the forearm extending?

A

Eccentric Isotonic Contraction (muscle lengthens)

26
Q

Which type of isotonic contraction can be said to be responsible for flexing?

A

Concentric Isotonic Contraction (muscle shortens)

27
Q

How does a higher load affect contraction speed?

A

Contraction speed is slower with higher load

28
Q

How does a higher load affect amount of shortening?

A

Amount of shortening is less with a higher load

29
Q

Define motor unit recruitment.

A

Activation of increasing number of motor units

30
Q

If a muscle contracts slowly and with little force what is happening with the amount of motor units recruited/activated?

A

Few motor units are recruited and activated

31
Q

If a muscle receives more frequent nerve impulses what is happening with the amount of motor units recruited/activated? How does this affect the actual contraction of the muscle?

A
  1. Additional motor units are recruited and activated

2. Muscle will contract faster and with more power

32
Q

Define Muscle Tone.

A

The residual state of contraction even when the muscle is at rest

33
Q

Define Muscle Fatigue.

A

The physiological inability to contract due to the shortage of available ATP

34
Q

When does muscle fatigue occur?

A

Occurs when metabolic production cannot keep up with demand & metabolic waste (lactic acid) is accumulating in the sarcoplasm.

35
Q

Define Oxygen Debt.

A

extra oxygen needed to replenish:

  1. oxygen reserves
  2. glycogen stores
  3. ATP
  4. creatine phosphate reserves
  5. conversion of lactic acid to pyruvic acid glucose

after vigorous muscle activity.

36
Q

What does lactic acid convert to?

A

pyruvic acid glucose

37
Q

Define Static Flexibility.

A

Ability of a muscle to be held at length

38
Q

Give an example of static flexibility.

A

To bend down to touch the floor and staying in that position

39
Q

Define Dynamic Flexibility.

A

Ability of a muscle to stretch quickly without being held in a stretched position

40
Q

Give an example of dynamic flexibility.

A

Bending down quickly to touch the floor and then springing back up

41
Q

Is rang of motion (ROM) greater with static or dynamic flexibility?

A

Dynamic

42
Q

In this unit, what are the 3 measuring instruments we used. Provide a clue as to what each one was.

A
  1. Goniometer (protractor instrument)
  2. Electromyography (EMG)
  3. Dynamometer (black instrument being clenched during an electromyography)
43
Q

How does greater flexibility affect range of motion?

A

Greater flexibility = greater range of motion

44
Q

What does a goniometer measure?

A

An instrument to measure static flexibility

45
Q

Define Abduction.

A

Move a limb laterally, away from the body

46
Q

Define Adduction.

A

Move a limb towards the body

47
Q

Define Circumduction.

A

Limb rotation

48
Q

Is the radius and ulna parallel in pronation or supination?

A

Supination

49
Q

Is the radius and ulna crossed in pronation or supination?

A

Pronation

50
Q

Describe the palm in supination.

A

Palm is up

51
Q

Describe the palm in pronation.

A

Palms are reserved/Palm down

52
Q

Describe the toes in dorsiflexion.

A

toes up

53
Q

Describe the toes in plantarfelxion.

A

toes down

54
Q

What is the dorsum of the foot?

A

top

55
Q

What is the plantar of the foot?

A

bottom

56
Q

What does contraction of the skeletal muscle creates changes in? (hint: used for an EMG)

A

Contraction of the skeletal muscle creates changes in the electric potential in overlying regions of skin

57
Q

An electromyography does what?

A

Detects & records cutaneous electrical activity caused by muscle contractions

58
Q

What is the recording of an electromyography called?

A

Electromyogram (EMG)

59
Q

What is a dynamometer used to measure?

A

An instrument that measures the force exerted by the contracting forearm muscles

60
Q

What other instrument is a dynamometer used in conjunction with?

A

electromyography