Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neurology- Physiology > The Somatomotor System > Flashcards

The Somatomotor System Flashcards

1
Q

What does the somatic motor system consist of?

A

All of the skeletal muscles and the elements of the nervous system which control them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The neural element of the somatic motor system comprises what two aspects?

A

Upper and lower motor neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where are the upper motor neurones found?

A

Within the brain, cerebellum and descending tracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where are the lower motor neurones found?

A

In the anterior horn of the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Complete the sentence: lower motor neurones are located in the ? horn of the spinal cord, with axons which project to the musculature in the ?

A

Anterior / peripheral nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Upper motor neurones supply input to where? To do what?

A

To lower motor neurones, to regulate their activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

As well as from upper motor neurones, where else do lower motor neurones receive input?

A

Proprioceptors and interneurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the two main types of lower motor neurone which are relevant in the somatic nervous system?

A

Alpha and gamma motor neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

‘Transmit information rapidly to muscle fibres to activate muscle contraction via the neuromuscular junction’ is the role of which type of motor neurone?

A

Alpha motor neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

‘Adjust the sensitivity of muscle spindles and stretch receptors to regulate muscle tone and power’ is the role of which type of motor neurone?

A

Gamma motor neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where is the primary motor cortex located?

A

The precentral gyrus of the frontal lobe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The biceps brachii and brachialis muscles work together as what?

A

Synergists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The biceps brachii and brachialis muscles oppose the triceps brachii and aconeus muscles. How is this described?

A

They are antagonists to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Axons of the LMNs exit the spinal cord where?

A

In the central roots, or via cranial nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Motor neurones are not distributed equally within the spinal cord. Why?

A

There is a greater number in the cervical enlargement to supply the upper limb, and a greater number in the lumbar enlargement to supply the lower limb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a motor unit?

A

An alpha motor neurone, and all of the skeletal muscles it innervates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the smallest functional component of the motor system?

A

The motor unit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The cell body of an alpha motor neurone will be found where?

A

In the anterior horn of the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a motor neurone pool?

A

A collection of alpha motor neurones that innervate a single muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Communication between motor neurones and muscle fibres occurs where?

A

The neuromuscular junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

A single action potential in an alpha motor neurone will cause a muscle fibre to do what?

A

Twitch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

If there is an extremely high firing rate of action potentials in an alpha motor neurone, meaning that there is no division between the action potentials, what does this cause the muscle to do?

A

Form a fused tetanus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why are small motor units with small cell bodies recruited before large ones?

A

Because they are more easily excited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Skeletal muscle fibres can be fast or slow. How do these differ?

A

In how fast myosin ATPTase splits ATP to provide energy for cross bridge formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is muscle tone?

A

The tension in a muscle

26
Q

What is muscle power?

A

The strength in a muscle

27
Q

Both muscle tone and muscle power are controlled by a combination of specialised sensory and motor components. What are some of these?

A

Golgi tendon organs, muscle spindles and both alpha and gamma neurones

28
Q

What does muscle power depend on?

A

The number of motor units which are recruited at one time (the more motor units, the more power)

29
Q

Complete the sentence: muscle tension is detected by specialised sensory receptors, the ? located at the ?

A

Golgi tendon organs / muscle-tendon border

30
Q

Complete the sentence: afferents from the Golgi tendon organ enter the ? and inhibit ?, thereby ? contraction and protecting the muscle from damage

A

Spinal cord / alpha motor neurones / reducing

31
Q

A deep tendon (myotatic) reflex is activated by what? This type of reflex has how many synapses?

A

Stretching the tendon / one synapse (monosynaptic reflex arc)

32
Q

During a deep tendon reflex, sensory input activates motor neurones directly to produce what?

A

Muscle contraction

33
Q

During a deep tendon reflex, the change in length (and the rate of change) of the muscle is registered by a sensory organ within the muscle known as what? This structure contributes to what?

A

The muscle spindle / non-conscious proprioception

34
Q

In a monosynaptic reflex arc, what triggers the whole thing starting?

A

The stretch of a muscle spindle

35
Q

In a monosynaptic reflex arc, after the muscle spindle has been stretched, what is activated?

A

The Ia primary afferent

36
Q

In a monosynaptic reflex arc, there is what type of synaptic transmission in the spinal cord? This is mediated by what?

A

Excitatory / glutamate

37
Q

In a monosynaptic reflex arc, once the excitatory synapse has gone ahead, there is activation of what? Which causes what?

A

The alpha motor neurone / muscle contraction and activation of gamma motor neurones

38
Q

In a monosynaptic reflex arc, once the gamma motor neurone has been activates, what does this do?

A

Changes the length of the spindle, allowing it to respond rapidly to additional changes if needed

39
Q

The activation of muscle spindles causes the muscles to do what? What is the function of this?

A

Contract / protect from overstretching and tearing

40
Q

The intrafusal fibres of muscle spindles are innervated by what?

A

Gamma motor neurones

41
Q

Stimulation of gamma motor neurones causes what?

A

The muscle spindle to contract

42
Q

Complete the sentence: during voluntary movement, alpha and gamma motor neurones are usually ? so that the intrafusal fibres contract in ? with the extrafusal fibres

A

Co-activated / parallel

43
Q

What are Golgi tendon organs innervated by?

A

Group Ib sensory afferents

44
Q

Where does proprioceptive information arise from?

A

Muscle spindles, Golgi tendon organs and joint receptors

45
Q

What activates the reverse myotatic reflex?

A

Increased muscle tension

46
Q

What happens to the flexor and extensor muscles in the flexor withdrawal reflex?

A

The flexor muscle is activated while the extensor muscle is inhibited

47
Q

What is the function of the flexor reflexes?

A

To withdraw a limb from a dangerous stimulus

48
Q

Complete the sentence: in the flexor withdrawal reflex, noxious stimuli cause the limb to ? by contraction of flexor muscles via ? interneurones and relaxation of extensor muscles via ? interneurones

A

Flex / excitatory / excitatory and inhibitory

49
Q

Complete the sentence: in the crossed extensor reflex, noxious stimuli will cause the limb to ? by contraction of extensor muscles via ? interneurones and relaxation of flexor muscles via ? interneurones

A

Extend / excitatory / excitatory and inhibitory

50
Q

The highest level of motor control is strategy - achieved by thinking, what is the aim of the movement and how can it best be achieved? What parts of the brain are responsible for this?

A

Neocortical association areas in the brain / basal ganglia

51
Q

The middle level of motor control is tactics - achieved by thinking, what sequence of muscle contractions and relaxations in time and space will fulfil the strategic aim? What parts of the brain are responsible for this?

A

The motor cortex and cerebellum

52
Q

The lowest level of motor control is execution - achieved by commanding the desired movement. What parts of the brain are responsible for this?

A

Brainstem and spinal cord

53
Q

Where do descending spinal cord tracts originate from?

A

The cerebral cortex and brainstem

54
Q

What are the two main types of descending spinal cord tract?

A

Lateral and ventromedial pathways

55
Q

What is the major lateral descending pathway?

A

Corticospinal tract

56
Q

What is the minor lateral descending pathway?

A

Rubrospinal tract

57
Q

Where do axons in the corticospinal tract cross over?

A

Most in the medulla to form the lateral tract, some in the spinal cord to form the ventral tract

58
Q

Lesions of the lateral descending pathways are associated with what problem?

A

Loss of ‘fractioned’ movements and slowing/impairment of accuracy of voluntary movement

59
Q

If there is damage to the corticospinal tract, why can this get better over time?

A

The rubrospinal tract is capable of compensating

60
Q

If there is damage to the corticospinal tract and the rubrospinal tract has compensated, what deficits may still be present?

A

Weakness of distal flexors and inability to move fingers

Neurology- Physiology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions