Control of Body Movement Flashcards
(109 cards)
1
Q
the control of body movement exists as a motor control __
A
hierarchy
2
Q
the lower level of motor control involves the coordination of tension of ___ and ____ muscle groups
A
synergistic and antagonistic
3
Q
low level motor control can execute ___
A
simple motor subprograms
4
Q
low level motor control can correct muscle action according to ___
A
proprioceptor input
5
Q
give some examples of simple movements that low level motor control can control
A
straighten legs, turn head
6
Q
sensory receptors can synapse onto what 2 types of neurons to elicit a motor response?
A
local circuit neurons in brainstem and spinal cord (that then synapse on motor neurons), or directly to motor neurone in the brain / spinal cord
7
Q
upper level motor control is responsible for coordination of __
A
sequences of skilled movements
8
Q
upper level motor control is responsible for the integration of ____ input
A
polymodal afferent
9
Q
upper level motor control is responsible for the correction of ___ according to ___ input
A
complex motor programs; polymodal
10
Q
upper level motor control is associated with the __ of complex movements
A
learning
11
Q
what brain elements are involved in upper level motor control?
A
cerebral cortex motor areas, basal nucleus, thalamus, cerebellum, motor centres in brain stem
12
Q
much of the input from muscle/tendons/skin synapses onto ____
A
local inhibitory interneurons
13
Q
a select class of proprioceptions (muscle spindles) can synapse directly onto ___ and directly __ neurons
A
motor neurons ; depolarize
14
Q
input from brain motor centers comes from ___ pathways that mostly synapse on ___ interneurons
A
descending; local inhibitory or excitatory
15
Q
local interneurons must integrate info from____ and ___ and modualte __
A
central sources and from the periphery; function of motor neurons
16
Q
what class of neurons makes up 90% of all neurons?
A
interneurons
17
Q
what are local interneurons?
A
interneurons that are close to the motor neurons they synapse onto
18
Q
interneurons projecting to distant targets cross the __ and control __ movements
A
midline; complex
19
Q
input to motor and local interneurons comes via ___ pathways
A
descending
20
Q
somatosensory information from the periphery is sensed by what 2 receptor types? where are each found?
A
- proprioceptors in muscles, tendon, and joint
2. somatosensory receptors, especially nociceptor
21
Q
input to motor neurons can come from ___ or ___
A
somatosensory in periphery or other spinal cord interneurons
22
Q
___ neurons are at the heart of local circuits in the spinal cord
A
somatic
23
Q
somatic neurons provide only output to ___ and constitute ___% of all neurons in the spinal cord
A
muscle fibers; 10
24
Q
t/f interneurons are very diverse in function/connectivity
A
true
25
what are local pattern generators?
interneurons that initiate repetitive movements as required for walking, swimming etc
26
monosynaptic reflex arc can synapse to ___ or ___
motor neuron of same muscle ; motor neurone pools of synergistic muscles
27
primary sensory neurons of muscle spindles are directly connected to ____ neurons in the __ that activate __
motor; spinal cord; the same muscles
28
if muscle spindles get activated, they will excite __ and lead to creation of __
motor neutrons; action potential
29
what are the 2 types of motor neurons that primary sensory neurons can activate?
alpha and gamma
30
what is the function of alpha motor neurons when activated by primary sensory neurons?
excite extrafusal muscles, leading to their contraction
31
what is the function of the gamma motor units when activated by primary sensory neurons?
excite intrafusal muscles, leading to their contraction
32
what is the function of muscle spindles?
provide positive feedback for motor neurons of muscles, adjusting the muscle force to the changed load
33
primary sensory neurons synapse onto synergistic muscles to ___ and also onto local inhibitory interneurons of antagonistic muscle to ___
aide in movement of the main muscle group; suppress action of antagonist to improve movement of main muscles group
34
what is the required connection to the somatosenosyr cortex that makes it possible to detect changes in load?
axon collaterals of muscle spindle receptors ascending in the dorsal column pathway
35
muscle spindles are what type of receptor?
proprioceptors
36
structure of muscle spindles
nerve endings of primary sensory neuron surrounded by connective tissue capsule and extrafusal muscle
37
muscle spindles can be found wrapped round ___
intrafusal fibers
38
muscle fibers are activated by __
passive stretch of muscle
39
t/f muscle spindle reflexes are easy to elicit and interpret and are clinically important
true
40
give an example of a muscle spindle reflex test and what it is clinically used fr
patellar reflex; helps determine damage to local motor circuit or reflex pathway
41
when Golgi tendon organs are activated, they provide ___ feedback on motor neurons of the same muscle and ___ contraction. This ic called ___
negative; inhibit ; feedback inhibition
42
Golgi tendon organs provide excitatory input to neurons innervating the ___ muscles in a process called
antagonistic ; reciprocal stimulation
43
what causes flexor muscles of shake when over-exerted?
alternating of increases and decrease in motor neurone activity
44
activation of ___ in the skin of limbs activates the withdrawal reflex
nociceptors
45
there is a __ reflex in the affected limb of a withdrawal reflex
flexor
46
in the withdrawal reflex there is excitatory input to motor neurons of the ___ flexor muscle
ipsilateral flexor muscle
47
in the withdrawal reflex, there is inhibitory input to motor neurons of the ___ extensor muscle
ipsilateral
48
what is the crossed extensor reflex?
the contraction of the contralateral extensor to allow for withdraw reflex on contralateral side
49
in the crossed extensor reflex, inhibitory input to motor neurons of the ___ muscle
contralateral flexor
50
in the crossed extensor reflex, there is excitatory input to motor neurons of the ___ muscle
contralateral extensor
51
during a withdrawal reflex, the nociceptor sends collateral axons up to the brain via the ___ pathway with the purpose __
anterolateral; alerting the brain that there was an incident
52
list 4 symptoms of damage to local motor circuits
1. weakness or loss of movement of affected muscles
2. loss of muscle tone (hypotonia)
3. loss of reflexes (areflexia)
4. muscle atrophy from disuse
53
what is the name for muscle weakness?
paresis
54
the primary motor cortex is major control region for ___
execution of voluntary movements
55
evidence to support the primary motor cortex being the major control region for voluntary movements
electrical stimulation at certain points results in contraction of different muscles on opposite side
56
the primary motor cortex is organized in what way?
topologically
57
parts of the body used for fine motor control are ____ represented. why is this?
positively disproportionately; there are more neurons there
58
the anterior premotor cortex is responsible for the _____ of movements
initiation
59
the primary motor and primary somatosensory cortexes are functionally very __ by ___
coupled; projection
60
t/f the neurons of the premotor cortex are often activated long before movement occurs
true
61
the premotor cortex is responsible for a selection of ___ movements, ___ and storage of ___
coordinated; learning; motor plans
62
the pyramidal system is a ___ motor pathway that is important to all __ movement
descending; voluntary
63
the pyramidal system is made of ___ pathways from neurons in motor cortex to motor neurons in the spinal cord and brain stem
direct
64
what is the most important tract of the pyramidal system?
corticospinal tract
65
the corticospinal tract carries info from the ___ to ___ in the ___ that control muscles of ___ and __
motor cortex ; local motor circuits; spinal cord; limbs and trunk
66
most of the fibers of corticospinal tract decussate at the ___
medulla
67
left motor cortex controls the __ side of the body
right
68
what is the second part of the pyramidal system? what does it control?
corticobulba controls the muscles of the head and neck
69
the pyramidal system forms a visible tract at the height of the ___ in the anterior part that is shaped like an inverted pyramid
medulla in the brainstem
70
the neurons in the motor cortex that project into the SC / brainstem are layer ___ motor neurons, often called ___to distinguish them from ___ in the SC
5; upper motor neurons; lower motor neurons
71
most of the neurons of the pyramidal system project to interneurons in the ___ and ___ where their info is integrated with __ info and control lower motor neurons
brain motor enters; SC; peripheral
72
t/f complex moments requires the use of both the pyramidal and extrapyramidal systems
true
73
the extrapyramidal system is part of the __ motor pathways
descending
74
the extrapyramidal system is responsible for ___ movements
involuntary
75
the extrapyramidal system consists of __ pathways form the motor cortex to the spinal cord neurons controlling the trunk and proximal limb muscles via ___
indirect; motor control enters in the brain stem
76
what 4 brain components are involved in the extrapyramidal system?
1. vestibular nuclei
2. reticular formation
3. superior colliculus
4. red nucleus
77
the vestibular tract controls __ and __
postural reflexes and maintain balanced position
78
the reticular formation controls __
muscle tone
79
the superior colliculus controls __
head ad neck movement towards stimulus
80
the red nucleus controls
movement of upper extremities in parallel to corticospinal tract
81
example of a trauma that might cause upper motor disorder
stroke in motor cortex or trauma to upper spinal cord
82
upper motor neuron disorders are caused by __
damage to motor cortex or corticospinal tract
83
what is lower motor neurone syndrome?
damage to local motor units in the spinal cord
84
what are 3 symptoms of upper motor neurone syndrome?
1. weakness (paresis) of affected muscle
2. loss of fine movements
3. spasticity (increased resistance to passive movements
85
what are there examples of spasticity is upper motor neurone syndrome?
1. increased muscle tone (hypertonia)
2. hyperactive stretch reflexes
3. clonus
86
what is clonus?
oscillatory contractions and relaxations in response to muscle stretch
87
what is the hallmark of upper motor neurone syndrome?
clonus
88
Parkinson's disease is caused by dysfunction of the
basla nuclei
89
Parkinson's disease is a ___ disease
sporadic neurodegenerative
90
what causes Parkinson's disease?
progressive loss of dopaminergic neurons in the substantial nigra, leading to decreased corpus striatum activity and higher inhibition of motor cortex
91
list the symptoms of Parkinson's
hypokineasia (diminished movements), bradykinesia (slowness), resting tremor and rigidity
92
what is given as treatment for Parkinson's? How does it work?
L-DOPA (Levdopa); transformed onto L-dopamine in the brain
93
the basal nuclei is a group of structures in the ___
fore/mid brain
94
what structures make up the basal nuclei? (4)
striatum, globus pallidus, subthalmic nucleus, substantia nigra
95
what is the role of the globes pallid us?
tonically inhibits initiation of movements
96
inhibition of movement causes by the globes pallid us can be received by actiavtion of the __ by the cortex
striatum
97
activation of the striatum inhibits the __, which de-represses the __
globus pallidus; motor cortex
98
activation of the striatum id facilitated by ___ input from the ___
dopaminergic; substantiated nigra
99
the basal nuclei acts as a __ on all voluntary movements
brake
100
t/f the basal nuclei must be relieved in order for movement to be initieated
true
101
neurons in the globus pallidus are __, persistently __ and project to motor nuclei in the __ and persistently ___ thalamic neurons which project into the motor cortex
inhibitory; active; thalamus; inhibit
102
huntintons disease is a __ disease
inherited neurodegenerative
103
what causes huntigtons disease?
atrophy of basal ganglia; diminished inhibition of motor cortex resulting in involuntary movements
104
what are the symptoms of huntington?
jerking movements (dyskinesia), mood change and personality, dementia
105
what is the treatment for huntigtons? How does it work?
dopamine antagonists; work by reducing striatal function, this making inhibition a little stronger
106
what are the 4 functions of the cerebellum?
1. receive input from motor cortex on intended movement
2. receives sensory input on actual movement
3. detects differences or motor error between intended band actual
4. corrects errors in real time
107
how does the cerebellum fix motor errors in real time?
through brainstem motor centres and sends information to cortical motor areas for future reference (motor learning)
108
list symptoms of cerebellar disease (4)
1. ataxia
2. intention tremor
3. unstable posture
4. difficulty learning new motor skills
109
what is ataxia?
jerky, imprecise movements, such as awkward gait
