Brainscape's Knowledge GenomeTM

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


See full index

Neurology > Functional Hierarchy of the Motor System > Flashcards

Functional Hierarchy of the Motor System Flashcards

1
Q

How are muscles directly controlled in the spinal cord?

A

Alpha motorneurons

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

What do brainstem nuclei control?

A

Posture and balance

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

What are the higher brain centres that control brainstem nuclei?

A

Cerebral cortex
Basal ganglia
Cerebellum

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

What is the result of lesions involving the lower motor neurons?

A

Flaccid paralysis

Muscle atrophy

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

What is the result of lesions involving the upper motor neurons?

A

Spasticity

Some paralysis, may be transient

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

What is the result of a corticospinal lesion?

A

Weakness (paresis)

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

What is the basis of the spatial map of body musculature in the spinal cord?

A

Proximal areas mapped by medial motorneurones

Distal areas mapped by lateral motorneurones

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

From where does the spinal cord receive descending input?

A

Brainstem

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

From where does the spinal cord receive direct cortical input?

A

Corticospinal (Pyramidal) tract

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

Where does sensory input enter the system?

A

Enters at all levels

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

In what form does sensory input enter the spinal cord?

A

Proprioceptors
Touch
Pain

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

In what form does sensory input enter the brainstem?

A

Vestibular system informs about balance

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

In what form does sensory input enter at the level of the cortex?

A 
Visual 
Olfactory 
Auditory 
Emotional 
Intellectual cues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the result of damage to sensory inputs?

A

Paralysis (at spinal cord)

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

Where is the stretch reflex found?

A

Every muscle

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

What is an example of a common stretch reflex?

A

Patellar tendon (knee jerk reflex)

17
Q

What is the basis of the stretch reflex?

A

Muscle spindle fibres send impulses to the spinal cord
Synapse in spinal cord
Efferent impulses to alpha motor neurones cause contraction of stretched muscle
Efferent impulses to antagonist muscles are damped

18
Q

What is the significance of the stretch reflex?

A

Detects level of spinal cord damage

Impaired reflexes indicate areas of nerve damage

19
Q

What type of information does the flexor reflex process?

A

Information from pain (nociceptors) in skin, muscles and joints

20
Q

How many synapses are involved in the flexor reflex?

A

Polysynaptic

21
Q

What does the flexor reflex do?

A

Withdraws body part away from painful stimulus and in towards the body

22
Q

How does the flexor reflex work?

A

Increased sensory action potentials cause increased activity in flexor muscles via excitatory interneurones
At the same time the antagonistic extensors are inhibited

23
Q

Where are interneurones activated in the flexor reflex?

A

Several spinal segments

24
Q

How is the body prevented from falling over during the flexor reflex?

A

Contralateral limb extends:
Excitatory interneurones crossing the spinal cord excite the contralateral extensors
Inhibition of contralateral flexors
Sensory info enters the brain in the contralateral spinothalamic tract

25
Q

Why is the flexor reflex slower than the stretch reflex?

A

Several interneurones so small synaptic delay

Nociceptive fibres have smaller diameter so conduct more slowly

26
Q

What is the function of the golgi tendon organ at spinal level?

A

Protective e.g prevents muscle tear due to excess load (can be overridden)

27
Q

How can you continue to hold something that is important, yet heavy, without dropping it?

A

Descending voluntary excitation of alpha motor neurones can override the inhibition from the golgi tendon organs and maintain contraction

28
Q

How ca the stretch reflex be overridden?

A

Descending inhibition hyperpolarizes the alpha motor neurones and stretch reflex can not be evoked

29
Q

What is the result of high gamma motor neurones?

A

Muscles become extremely resistant to stretch (spastic)

30
Q

What area of the spinal cord will stretch reflex affect?

A

One or two spinal segments (highly localised)

31
Q

What area of the spinal cord will flexor reflex affect?

A

Spreads through several spinal segments

32
Q

What is the effect of a more powerful pain stimulus?

A

Greater spinal spread, larger response

33
Q

What is the function of facilitation?

A

Increases the effect of sensory input

34
Q

What is the Babinski sign?

A

Extension but not flexion of foot, toes fan yp and out (indicates damage/disruption to corticospinal tract)

35
Q

What are the consequences of spinal shock?

A

Loss os sensation

Loss of bowel, bladder, sexual regulation

36
Q

What causes spinal shock?

A

Loss of supraspinal excitation, reflexes not evoked for 2-6 weeks

37
Q

What is clonus?

A

Oscillatory muscle contraction/relaxation caused by stretch

Neurology (39 decks)

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