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Anatomy > ✅Voluntary Motor Control > Flashcards

✅Voluntary Motor Control Flashcards

1
Q

What is a motor unit made up of?

A

a motor neuron and the skeletal muscle fibers innervated by that motor neuron’s axonal terminals.

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2
Q

Why do groups of motor units work together?

A

To coordinate the contractions of a single muscle.

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3
Q

What are all the motor units in a muscle called?

A

A motor pool

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4
Q

What are All muscle fibres are innervated by?

A

1 motoneurone

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5
Q

What does each moroneurone innervate?

A

Many muscle fibres within the same muscle

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6
Q

How many types of motor units are there?

A

3

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7
Q

What are the 3 types of motor units related to?

A

The size of the motoneurone, the number of muscle fibres innervated and the mechanical properties of those fibres

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8
Q

Muscle fibers of different motor units are intermingled. True or False?

A

True

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9
Q

What happens as a result of the muscle fibres being intermingled?

A

The forces applied to the tendon remain roughly balanced regarding which motor units are stimulated.

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10
Q

What are muscle properties determined by?

A

The proportion and type of motor units they contain.

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11
Q

What are the two types of muscles?

A

Fast and Slow

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12
Q

What are fast muscles?

A

Pale muscle fibres, when simulated, they contract rapidly

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13
Q

What are slow muscles?

A

Red muscle fibres, when simulated, they contract slowly.

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14
Q

How are differences reflected?

A

in contractile and biochemical characteristics of muscle fibres in different motor units

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15
Q

What is type 1 muscle fibre?

A

Long distance, slow twitch , low fatigue rate (mo Farrah)

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16
Q

What is type 2A muscle fibre?

A

400/800m, fast twitch oxidative, medium fatigue rate/

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17
Q

What is type 2B muscle fibre?

A

Short sprint, fast twitch glycolytic, high fatigue rate. (Usain Bolt)

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18
Q

What is recruitment (with regards to motor units)

A

Multiple motor unit summation

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19
Q

What happens in a whole muscle or group of muscles? (Motor unit recruitment)

A

smooth motion and increasing tension are produced by slowly increasing the size or number of motor units stimulated.

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20
Q

What is the size principle?

A

Under normal circumstances, MU are recruited to movement before larger ones

21
Q

When is maximum tension achieved?

A

When all motor units reach tetanus, can be sustained only a very short time

22
Q

Describe white muscles

A
  • mostly fast fibres

- Pale ( chicken breast)

23
Q

Describe red muscles

A
  • mostly slow fibres

- dark (chicken legs)

24
Q

What are most human muscles made up of?

A

Mixed fibres:

  • fast
  • slow
  • intermediate
25
Q

Describe 5 features of fast fibres. (Usain Bolt)

A

• Contract very quickly
• Have larger diameter, large glycogen reserves,
few mitochondria
• Poor oxidative enzyme capacity
• High anaerobic enzyme activity
• Have strong contractions, fatigue quickly

26
Q

Describe 6 features of slow fibres (Mo Farrah)

A

• Are slow to contract, slow to fatigue
• Have small diameter, small mitochondria
• Have high oxygen supply
• Large oxidative enzyme activity
• Low anaerobic enzyme activity
• Contain myoglobin (red pigment, binds oxygen)

27
Q

Describe 5 features of intermediate fibres.

A

• Are mid-sized
• Have low myoglobin
• Have more capillaries than faster fibres, slower
to fatigue
• Intermediate oxidative capacity
• High anaerobic enzyme activity

28
Q

What is sarcopenia?

A

Age related muscle atrophy

29
Q

What happens with age?

A

There is a loss of larger motor units

30
Q

Fast and high force movements are difficult for what age group?

A

Elderly

31
Q

What does the cerebral cortex do with regards to movement?

A

Complex and skilled motor acts.

32
Q

What does the spinal cord do with regards to movement?

A

Postural,protective reflexes, locomotion

33
Q

What does the brain stem do with regards to movement?

A

Breathing, chewing, swallowing and eye movement.

34
Q

What does the basal ganglia do with regards to movement?

A

Initiation of motor behaviour

35
Q

What do the hypothalamus do with regards to movement?

A

Eating/drinking

36
Q

What are fine motor skills?

A

Speech, hand and finger control.

37
Q

What are the three stages of the basic functions of descending tracts?

A
  1. Cortico- and Rubrospinal
  2. Reticulospinal
  3. Vestibulospinal
38
Q

What are the two steps of the Cortico stage?

A
  1. Transmission of commands for skilled movements.

2. Corrections of motor patterns generated by the spinal cord.

39
Q

What are the two stages of the reticulospinal stage?

A
  1. Activation of spinal motor programs for stepping and other stereotypic movements
  2. Control of upright body posture.
40
Q

What is the step at the vestibulospinal stage?

A

Generation of tonic activity in antigravity muscles

41
Q

What is the convergent information flow in motor planning?

A

Sensory periphery/eye -> input from muscles, skin and joints/ location and movement of objects-> somatic afferent pathways/Visual afferent pathway -> Primary Somatic Sensory Cortex/ Primary Visual Cortex -> SENSORY SYSTEM -> MOTOR SYSTEM-> Primary Motor Cortex -> Direct system/ Indirect System -> spinal cord/ spinal cord -> Muscles of hand and arms/ reflexes and postural adjustments.

42
Q

What happens when we learn a movement?

A

we first execute it very slowly because it cannot be adequately programmed.

43
Q

What happens because a movement cannot be adequately programmed?

A

Instead, it is performed largely by intense cerebral concentration as well as with the constant updating via the cerebellum.

44
Q

What happens With practice and the consequent motor learning?

A

a greater amount of the movement can be programmed and the movement can be executed more rapidly.

45
Q

What happens with very rapid movements?

A

we rely entirely on pre-programming because there is no time for on-target correction once the movement has begun.

46
Q

What do we have to envisage when carrying out skilled movement?

A

there is an immense integration of neuronal activities in interacting dynamic loops.

47
Q

Where are mirror neurons found?

A

in the premotor cortex

48
Q

When do they discharge?

A

Both when making a movement, or when observing a movement being performed by another.

49
Q

What is voluntary movement?

A

It needs sensory feedback
It helps brain visualise movement
It helps brain plan how to sequence a movement (motor programme)
Helps update and automate trained actions.

Anatomy (20 decks)

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