Chapter 1 pt. 2 Flashcards

1
Q

Does a muscle contraction require energy?

A

Yes

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2
Q

How is energy created for a muscle contraction?

A

ATPase, located on the myosin head, splits the ATP to yield ADP, inorganic phosphate (Pi), and energy

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3
Q

What does the energy in a muscle contraction do?

A

It powers the tilting of the myosin head

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4
Q

How is energy required for muscle relaxation?

A

Calcium is returned to the sarcoplasmic reticulum by an active calcium pumping system that requires ATP

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5
Q

What happens after calcium is pumped back into the SR for muscle relaxation?

A

Troponin and tropomyosin return to the resting conformation by covering the active sites

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6
Q

What are type 1 muscle fibers?

A

Slow twitch fibers

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7
Q

What are type b/x muscle fibers?

A

Fast twitch fibers

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8
Q

How long does it take type 1 fibers to reach peak tension when stimulated?

A

110 ms

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9
Q

How long does it take type b/x fibers to reach peak tension when stimulated?

A

50 ms

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10
Q

What muscle fibers make up 50% of muscles

A

Type 1

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11
Q

What muscle fibers make up 25% of muscles?

A

Type 2a and 2x

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12
Q

What muscle fibers make up 1-3% of muscles?

A

Type 2c

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13
Q

How are muscle fiber types analyzed?

A

Muscle biopsy

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14
Q

What is the function of muscle biopsy?

A

allows us to study muscle fibers and gauge the effects of acute exercises and chronic training on fiber composition

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15
Q

What muscle fiber has a slow form of myosin ATPase?

A

Type 1

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16
Q

What muscle fiber has a fast form of myosin ATPase?

A

Type 2

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17
Q

What is gel electrophoresis?

A

A method for identifying fiber types by chemically separating the different types of myosin molecules

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18
Q

Which muscle fiber has a more developed sarcoplasmic reticulum?

A

Type 2

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19
Q

What determines whether a muscle fiber is type 1 or type 2?

A

The a-motor neuron

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20
Q

How many muscle fibers does an a-motor neuron innervate in type 1 motor units?

A

less than or equal to a cluster of 300 muscle fibers

21
Q

How many muscle fibers does an a-motor neuron innervate in type 2 motor units?

A

more than or equal to 300 muscle fibers

22
Q

All muscle fibers reach peak at?

A

20% peak force

23
Q

What muscle has a very high percentage of type 1 fibers in everyone?

A

The soleus muscle (behind the gastrocnemius in the calf)

24
Q

What type of muscle fiber has a high level of aerobic endurance?

A

Type 1

25
Q

Type 1 fibers are efficient at producing ATP from the oxidation of?

A

Carbohydrates and fats

26
Q

Aerobic means?

A

presence of oxygen

27
Q

What type of muscle fiber performs better anaerobically?

A

Type 2

28
Q

Anaerobic means?

A

Without oxygen

29
Q

What type of muscle fiber fatigues the easiest and has limited endurance?

A

Type 2a

30
Q

Which type 2 fiber is used in shorter, higher-intensity endurance events like mile run or 400m swim?

A

Type 2a

31
Q

Which type 2 fiber is used in highly explosive events like the 100m dash or 50m sprint swim?

A

Type 2b

32
Q

What determines our individual muscle fibers?

A

The a-motor neuron

33
Q

How are muscle fibers differentiated?

A

Based on their neuron

34
Q

Endurance and resistance training reduce the percentage of what type of muscle fiber?

A

Type 2b

35
Q

Endurance and resistance training increases a fraction of what type of muscle fiber?

A

Type 2a

36
Q

As we grow older we tend to lose what type of muscle fibers?

A

Type 2

37
Q

What is the order recruitment of motor units?

A

Type 1, type 2a, type 2b

38
Q

What is the principle of orderly recruitment?

A

The ranking of motor units in a given muscle

39
Q

What type of muscle fiber has less force production?

A

Type 1

40
Q

What type of muscle fiber has more force production?

A

Type 2

41
Q

What is a static muscle contraction?

A

A muscle generates force without movement because the joint angle does not change

42
Q

Concentric means?

A

Shortening

43
Q

Eccentric means?

A

Lengthening

44
Q

What are considered dynamic contractions?

A

Concentric and eccentric contractions

45
Q

What is happening during a concentric contraction?

A

Thin filaments are pulled toward the center of the sarcomere

46
Q

What is happening during an eccentric contractions?

A

Force is exerted when extending the elbow

47
Q

What is rate coding?

A

The frequency of stimulation of the motor unit

48
Q

What are the 3 types of rate coding

A

Twitch, summation, tetanus

49
Q

What are the 4 things that generate force?

A

Motor unit recruitment, rate coding, length-tension relationship, and speed-force relationship