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Physiology Exam 2 > Motor Control (Part 1) > Flashcards

Motor Control (Part 1) Flashcards

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1
Q

More than half of the somatotopic primary motor cortex controls what two things?

A

Hands & speech

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2
Q

To which two areas are projections made from the premotor area?

A

Primary motor cortex and basal ganglia

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3
Q

The supplemental motor area works with which other area to provide its movements?

A

Premotor area

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4
Q

What movements are provided by the supplemental motor area?

A

Attitudinal movements, fixation movements, positional moments of the head and eyes, background for finer motor control of arms/hands

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5
Q

The majority (60%) of the corticospinal tract originates from where?

A

Premotor and supplemental areas

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6
Q

Which part of the corticospinal tract’s fibers cross midline?

A

Lateral

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7
Q

Which part of the corticospinal tract’s fibers stay ipsilateral?

A

Ventral (Anterior)

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8
Q

Which spinal tract descends via the posterior limb of the internal capsule between the caudate and putamen?

A

Corticospinal

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9
Q

Which spinal tract forms the pyramids of the medulla?

A

Corticospinal

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10
Q

Spinal preparation exhibits what type of change?

A

Flaccidity (flaccid or floppy paralysis)

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11
Q

Decerebrate preparation exhibits what type of change?

A

Decerebrate rigidity

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12
Q

Decorticate preparation exhibits what type of change?

A

Decorticate spasticity

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13
Q

Which type of transection involves all tracts being cut and the cord completely being isolated from the brain?

A

Spinal preparation

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14
Q

Which type of transection occurs at the mid collicular level?

A

Decerebrate preparation

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15
Q

Which type of transection is a destruction of the cerebral cortex?

A

Decorticate spasticity

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16
Q

With which type of transection are extensors tonically hyperactive?

A

Decerebrate preparation

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17
Q

What is tonically excited with a decorticate preparation?

A

Upper areas of the reticular formation that are no longer under inhibitory cortical influence (release phenomenon)

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18
Q

What is a visual example found in humans of decorticate spasticity?

A

Hemiplegic side after stroke

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19
Q

Decorticate spasticity is responsible for what percentage of intracerebral hemorrhages?

A

60%

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20
Q

What can occur with the small arteries in the internal capsule during decorticate spasticity?

A

Rupture or thrombosis

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21
Q

Which type of transection experimental procedure is useful for the study of reflexes?

A

Decerebration

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22
Q

Where is the transection of the midbrain usually?

A

Intercollicular level

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23
Q

What is lost with decerebration?

A

Sensation

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24
Q

What is interrupted with decerebration?

A

Cortical descending pathways

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25
What remains intact with decerebration?
Brain stem control
26
What type of reflexes are suppressed with decerebration?
Flexion
27
What type of reflexes are exaggerated with decerebration?
Stretch
28
How are stretch reflexes exaggerated with decerebration?
Selective excitation of gamma motor neurons
29
What is the prognosis of a patient with brainstem damage signs of decerebration?
Poor
30
What occurs initially with a spinal cord transection?
All cord functions including spinal reflexes are depressed
31
When do the spinal cord neurons tend to gradually regain excitability following a spinal cord transection?
Days to weeks
32
What can possibly occur when spinal cord neurons regain excitability after a spinal cord transection?
Hyperactivity
33
What is a mass reflex?
Spinal cord becoming excessively active
34
In spinal shock, what happens to the blood pressure?
Falls dramatically
35
In spinal shock, what happens to all skeletal muscle reflexes integrated in the cord?
Blocked
36
What happens specifically to the control of bladder and colon evacuation during spinal shock?
Suppressed control
37
What do the pontine reticular nuclei stimulate?
Axial trunk and extensor muscles that support the body against gravity
38
From where do the pontine reticular nuclei receive stimulation?
Vestibular nuclei and deep nuclei of the cerebellum
39
Through which tract are excitatory signals transmitted from the pontine reticular nuclei?
Pontine (medial) reticulospinal tract
40
What do the medullary reticular nuclei inhibit?
Axial trunk and extensor muscles that support the body against gravity
41
Through which tract are inhibitory signals transmitted from the medullary reticular nuclei?
Medullary (lateral) reticulospinal tract
42
From where do the medullary reticular nuclei receive input?
Cortex, red nucleus, and other motor pathways
43
What does the medullary reticular nuclei do in reference to the pontine reticular nuclei?
Counterbalance its excitatory signals
44
What effect on tone do the medullary reticular nuclei have?
Enables increase or decrease depending on function needing to be performed
45
Is the ventral corticospinal tract ipsilateral or contralateral?
Ipsilateral
46
Are the reticulospinal tracts ipsilateral or contralateral?
Ipsilateral
47
Are the vestibulospinal tracts ipsilateral or contralateral?
Ipsilateral
48
Which descending tracts originate from the lateral vestibular nucleus to mainly extensors?
Vestibulospinal
49
Is the lateral corticospinal tract ipsilateral or contralateral?
Contralateral
50
Is the rubrospinal tract ipsilateral or contralateral?
Contralateral
51
Is the tectospinal tract ipsilateral or contralateral?
Contralateral
52
Which descending tract innervates mainly flexors?
Rubrospinal
53
Which descending tract innervates cervical musculature only?
Tectospinal
54
Which descending tract involves superior colliculus-orienting reactions?
Tectospinal
55
Which two tracts are found in the lateral aspect of the spinal cord?
Lateral corticospinal and rubrospinal
56
Which descending tract controls more distal muscles of the limbs?
Rubrospinal
57
Stimulation of about how many pyramidal cells are necessary to achieve muscle contraction?
50-100
58
Which type of pyramidal cell signal is excessively excited at the onset of contraction to initiate muscle contraction?
Dynamic
59
Which type of pyramidal cell signal fires at a slower rate to maintain contraction?
Static
60
Signals for movement output to the premotor cortex directly and indirectly via what two structures?
Basal ganglia and cerebrocerebellum
61
What is the execution pathway of voluntary movement as corticospinal projections?
Premotor cortex to primary motor cortex to spinal cord
62
Where can signals from the primary motor cortex all go to during the execution phase of voluntary movement?
Spinocerebellum
63
Feedback from the periphery during the execution phase of voluntary movement passes through what structure to get back to the primary motor cortex?
Spinocerebellum
64
What is a major factor in postural control?
Variation of threshold of spinal stretch reflexes
65
What are the three types of postural reflexes?
Vestibular, tonic neck, and righting
66
What is the vestibular apparatus?
Organ that detects sensations of equilibrium
67
What makes up the vestibular apparatus?
Semicircular canals, utricle, and saccule
68
Where is the vestibular apparatus located?
In the petrous portion of the temporal bone
69
What information does the vestibular apparatus provide?
Positional and information on the movement of the head in space
70
What actions does the vestibular apparatus aid with?
Maintaining body balance and helping coordinate movements
71
What is the sensory part of both the utricle and saccule?
Macula
72
What is imbedded in the gelatinous layer of the macula in the vestibular apparatus?
Small calcium carbonate crystals
73
What causes the depolarization or hyper polarization of the macula in the vestibular apparatus?
Directional sensitivity of hair cells
74
What does the macula of the vestibular apparatus sense?
Orientation of the head with respect to gravity and linear acceleration
75
Which macula lies mainly in the horizontal plane?
Utricle
76
Which macula lies mainly in the vertical plane?
Saccule
77
Which macula is important in determining orientation of the head when the person is upright?
Utricle
78
Which macula is important in determining orientation of the head when the person is lying down?
Saccule
79
As the head begins to rotate, what is stimulated in the vestibular apparatus?
Semicircular canals
80
What is the sensory organ of rotation located in the semicircular canals?
Crista ampullaris
81
What is the loose gelatinous tissue mass on top of the crust ampullaris?
Cupula
82
In what direction do the three pairs of semicircular canals lie in reference to one another?
Bilaterally at 90 degrees to one another (anterior, horizontal, and posterior)
83
What are the three pairs of semicircular canals in reference to planes?
Right anterior and left posterior, right and left horizontal, left anterior and right posterior
84
What type of fluid and ions fill the semicircular canals?
Endolymph, K+
85
What happens to the endolymph in the semicircular canals when the head begins to rotate?
Begins to lag behind and bend the cupula
86
The recapture potential generator from head rotation and the endolymph in the semicircular canals alters the firing rate of which cranial nerve?
VIII
87
To where does cranial nerve VIII project?
Vestibular nuclei
88
What two things do the semicircular canals detect?
Rotational acceleration and deceleration
89
After rotation, what happens to the firing rate of cranial nerve VIII?
Opposite effect occurs (ex. when you are rotating left and stop, you feel like you're going to the right briefly afterward)
90
Right or clockwise rotation will stimulate which semicircular canal?
Right (always symmetrical)
91
Stimulation of semicircular canals is associated with increased tone of which muscles?
Extensors on the same side
92
Stimulation of semicircular canals is associated with what condition?
Nystagmus (specifically the slow component)
93
The vestibular nuclei make connections with which three cranial nerves?
III, IV, and VIII (along with the cerebellum)
94
What is the slow component of nystagmus?
The tracking that can be initiated by the semicircular canals
95
What is the fast component of nystagmus?
The jumping ahead to a new focal spot initiated by brainstem nuclei
96
What part of the cerebellum do the semicircular canals work closely with?
Flocculonodular lobe
97
What are extra factors of equilibrium that can provide information about the orientation of the head with the rest of the body?
Neck proprioceptors, visual signals
98
To where do neck proprioceptors project?
Vestibular nucleus and cerebellum
99
How can the prevention of a feeling of malequilibrium occur?
Cervical joint proprioceptors can override signals from the vestibular apparatus

Physiology Exam 2 (2 decks)

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