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Neuromotor Function 1 > Lecture 9- Motor Systems, Cortical Pathways > Flashcards

Lecture 9- Motor Systems, Cortical Pathways Flashcards

1
Q

What are the 4 functions of the motor system

A
  1. goal of movement and movement planning that best achieves the goal
  2. squencing of muscle contraction to smoothly and accurately achieve goal
  3. execution of goal-directed movement
  4. mechanics of the whole body and adjusts postural responses in adaptive ways for movement
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2
Q

the motor system is _____ motor control from the cortex and is the control of discrete ______ _____

A
  • decending

- voluntary movements

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3
Q

what is motor homunclus?

A

disproportionate representation of hands, face and mouth in primary motor cortex

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4
Q

upper motor neuron (UMN) is the ___ order neuron

A

1st

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5
Q

UMN carries information from ____ to ____ and ____ ___

A
  • cortex
  • brainstem (corticobulbar tract)
  • spinal cord (corticospinal tract)
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6
Q

lower motor neuron (LMN) is the _____ order neuron

A

2nd

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7
Q

LMN carries information in the ____ and ___ ___ that directly projects to the ____ in the periphery

A
  • brainstem
  • spinal cord
  • muscles
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8
Q

T/F: lateral motor system controls movements of the limbs

A

True

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9
Q

Medial motor system controls what?

A
  • posture
  • balance
  • axial control
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10
Q

what are the 2 corticospinal tracts?

A
  • lateral corticospinal tract

- anterior corticospinal tract

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11
Q

corticobulbar are fibers projecting from ____ to nuclei in _____

A
  • cortex

- brainstem

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12
Q

corticobulbar tract travels with the _____ tract in the cerebral ____ in the midbrain

A
  • corticospinal

- peduncles

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13
Q

corticobulbar tract projects to motor nuceli of what cranial nerves?

A
  • CN 5, 7, 9, 10, 11, 12
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14
Q

corticobuulbar tract controls LMN innverating muscles of the ___, ____, ____ and ____

A
  • face
  • tongue
  • pharynx
  • larynx
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15
Q

T/F: over 50% of cotricospinal tract fibers originate in the primary sensory cortex

A

False: over 50% of cotricospinal tract fibers originate in the primary MOTOR cortex

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16
Q

other tract fibers of the corticospinal tract originate from what 3 areas other then the primary motor cortex

A
  • motor association cortex (premotor and supplmentary motor cortex),
  • somatosensory cortex
  • related association areas
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17
Q

describe corona radiata

A
  • initial path of the corticospinal and cortocobulbar tracts

- travel from the cortical regions, axon fibers enter upper portion of cerebral white matter called corona radiata

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18
Q

describe internal capsule

A
  • large fiber bundle carrying most of the axons running to and from the cerebral hemispheres
  • corticospinal and corticobulbar tract pathway is from the corona radiata to the internal capsule
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19
Q

what are the 3 parts of the internal capsule

A
  • anterior limb
  • genu
  • posterior limb
20
Q

describe the pathway in which the corticobulbar tracts take from cortex to brainstem

A

cortical regions –> corona radiata –> internal capsule –> basis ppedunculi (in midbrain)–> brain stem cranial nerves (project onto associated CN)

21
Q

the corticospinal and corticobulbar tracts enter the midbrain at the ___ portion of cerebral peduncles called the ____ ____

A
  • ventral

- bassis peduculi

22
Q

corticobulbar tract terminates on motor nuclei for CN on _____ side to control LMN

A
  • opposite
23
Q

describe the pathway in which the corticospinal tracts take from cortex to brainstem

A

cortical regions –> corona radiata –> internal capsule –> basis pedunculi (in midbrain)–> ventral pons–> medulla (which becomes the spinal cord)

24
Q

T/F: the corticospinal trac form the pyramids at ventral medulla

A

true

25
Q

the corticospinal tract axons cross to the opposite side at the ____-____ junction also called the ____ ____

A
  • cervical-medullary junction

- pyramid decussation (great motor cross over)

26
Q

corticospinal tract= ____ % cross over while ____% remain on ipsilateral course

A
  • 85%

- 15%

27
Q

corticospinal tract fibers that have crossed to controlateral side enter ____ colummns of spinal cord and form the ____ _____ tract

A
  • lateral columns

- lateral cotricospinal tract

28
Q

corticospinal fibbers that did not cross over course down the spinal cord on the ____ columns forming the _____ ______ tract

A
  • anterior columns

- anterior corticospinal tract

29
Q

functions of the lateral corticospinal tract (lateral motor system)

A
  • controls movement of the extremities
30
Q

functions of the anterior corticospinal tract (medial motor system)

A
  • controls proximal axial and girdle muscles
31
Q

for the lateral motor system: the pyramidal decussation allows clinicians a clue about location of lesion on corticospinal tract…. the right motor cortex directly commands movement on what side?

A
  • left
32
Q

for the lateral motor system: the pyramidal decussation allows clinicians a clue about location of lesion on corticospinal tract…. right side of body movements get controls by what side of the motor cortex?

A
  • left
33
Q

T/F: lesions above pyramidal decussion produce ipsilateral deficits in both upper and lower extremities

A

false: contralateral deficits

34
Q

lateral corticospinal tract fibers controlling upper extremity are ___ to those controlling lower extermity

A
  • medial
35
Q

T/F: lesions below medulla produce ipsilateral deficits below level of lesion

A

true

36
Q

LMB terminate at motor end plates of skeletal muscles of limb… known as _____ _____

A
  • neuromuscular junction
37
Q

lateral corticospinal tract enter spinal cord and terminate on what 2 areas?

A
  • interneurons (modulatory function)

- ventral horn cells of the lower motor neurons (anterior horn cells)

38
Q

what are the functions of the lateral corticospinal tract?

A
  • strongly influences muscles of the extremities; Especially distal muscles important for execution of fine, skilled movements
  • tends to have a facilitative action upon anterior horn cells with motor neurons to flexor muscles
    inhibitory influence on anterior horn cells of motor neurons to extensor muscles
  • tends to have a facilitative action upon gamma motor neurons
  • Also projects on sensory neurons in the dorsal horn and control the amount of information to be sent to the CNS
39
Q

what is the most common lession for corticospinal tract and examples. what are the other causes?

A
  • vascular
  • typically middle cerebral artery or vertebrobasilar artery
  • other causes: tumor, trauma, demylinating diseases
40
Q

what do we typicall find when lesions of the lateral corticospinal tract occur

A
  • hypertonia (increased muscle tone): increased resistance to passive stretch
  • increased velocity-dependent muscle response (spasticity)
  • increased deep tendon reflexes (hyperreflexia)
  • Babinski’s sign- positive
  • Clonus- positive
  • muscle weakness
41
Q

what is the function of the anterior corticospinal tract

A
  • Critical to control of bilateral axial muscles and muscles of shoulder and pelvic girdles
42
Q

T/F: the anterior corticospinal tract first project on the interneurons which in turn project on anterior horn cells

A

true

43
Q

upper motor neurons contributing to lateral corticospinal tract originate predominantly in _____ _____ cortex

A
  • primary motor cortex
44
Q

upper motor neurons contributing to anterior corticospinal tract originate mainly in _____ _____ cortex

A
  • motor association cortex
45
Q

T/F: unilateral lesions of the medial motor system cause deficits on ipsilateral side

A

False: Since medial motor systems terminate on interneurons that project to both sides of spinal cord unilateral lesions of medial motor systems do not produce obvious deficits

Neuromotor Function 1 (21 decks)

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