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Undeleted > Neuromotor System > Flashcards

Neuromotor System Flashcards

0
Q

Nuclear bag fibers
Cell nuclei arrangement:
Deformation signals info about:

A

Jumbled together in middle

Rate of change (velocity) of muscle length

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1
Q

Nuclear chain fibers
Cell nuclei arrangement:
Deformation signals info about:

A

Aligned in single row

Static length of muscle

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2
Q

Spindle afferents that only innervate nuclear chain fibers

A

Type II

Signal muscle immediate length

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3
Q

Spindle afferents that wrap around both nuclear chain and nuclear bag fibers

A

Type 1a

Signal both muscle length an velocity

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4
Q

Muscle tone is fine-tuned by tonic discharge of ____ activated by ______ pathways (2)

A

Gamma motor neurons

Reticulospinal, vestibulospinal

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5
Q

Coordinates muscle tone in every muscle of body by modulating alpha motor neurons and gamma motor neuron firing frequency

A

Cerebellum

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6
Q

Contractile force of motor unit =

A

Force-generating capabilities of muscle’s fiber type x # fibers innervated by motor neuron

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7
Q

Dorsal groups of motor neurons innervate ___

A

flexors

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8
Q

Ventral groups of motor neurons innervate ___

A

Extensors

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9
Q

Medial groups of motor neurons innervate ____

A

axial (proximal) muscles

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10
Q

Lateral groups motor neurons innervate ____

A

Distal muscles

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11
Q

Lateral dorsal groups motor neurons innervate ___

A

most distal muscles (hands)

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12
Q

5 main descending motor systems

A 
Corticospinal
Corticobulbar
Reticulspinal
Vestibulospinal
Tectospinal 
(Rubrospinal) unimportant
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13
Q

Project their axons across different levels of cord.

Yoke together proprioceptive systems and alpha/gamma motor neurons in networks called ____

A

Propriospinal interneurons in intermediate zone

Central pattern generators

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14
Q

Input of central pattern generators

A 
Sensory fibers
Supraspinal neurons (corticospinal system)
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15
Q

Output of central pattern generators

A

(mostly inhibitory) alpha and gamma motor neurons

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16
Q

Intrinsic hand muscle motorneurons are located in _____

A

Dorsal part of ventral horn at C7-T1

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17
Q

Lesion of facial nucleus will result in ____

A

contralateral lower facial hemiparisis

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18
Q

Major functions of corticobulbospinal tract

A

Individual muscle control
Facilitation of flexors
Command system for activating central pattern generators

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19
Q

Rubrospinal system
Originates in:
Function:

A

Red nucleus

Facilitate neck and upper limb flexors

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20
Q

Tract involved in integrating CPG function

A 
Reticulospinal tract
By facilitating (MRST) or inhibiting (LRST) stereotypic movements and compound limb movements
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21
Q

Reticulospinal system involved in:

A

Maintenance of posture
Modulation of muscle tone
CPG coordination

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22
Q

Damage at or below red nucleus when lateral corticospinal tract is disrupted causes ____

A

decerebrate rigidity

Lateral vestibulospinal tract’s bias for extension is unopposed

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23
Q

Tracts that have biased flexion

A

Rubrospinal

Medullary reticulospinal

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24
Q

Tracts that have biased extension

A

Lateral vestibulospinal tract

Pontine reticulospinal tract

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25
Q

Functions of vestibulospinal tract and tectospinal tract

A

Postural control through facilitation of extensors

Coordination of head, neck and axial spine movements

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26
Q

Central control on motor system: planning and preparation

A

Frontal lobe

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27
Q

Central control of motor system: motor or procedural learning

A

basal ganglia

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28
Q

Central control of motor system: hitting the target

Accuracy and sequencing of complex voluntary movements

A

Cerebellum

29
Q 
Premotor area (PMA) involved in \_\_\_\_\_\_ 
Represents:
A

Planning and preparing movements in response to external cues, particularly visual
Ownership of limbs and perception of their movements (sense of agency)

30
Q

Supplementary motor areas (SMA) involved in ____

A

Internally generated movements

31
Q

Lesion of lateral corticospinal tract in spinal cord produce ____

A

ipsilateral loss f voluntary movement below level of lesion, mostly in distal extremities

32
Q

Lesion of corticospinal tract occurring above pyramidal decussation will cause _____

A

CONTRALATERAL paralysis/paresis

33
Q

Lesion of hypoglossal nucleus will cause (3) (ipsilateral/contralateral) signs:
Location of nucleus:

A

1.Tongue deviate TOWARD side of lesion
2.Dysphagia (swallowing)
3.Dysarthria (articulation)
CONTRALATERAL
Medulla

34
Q

Oculomotor nuclear complex located in:

A

midbrain

35
Q

Oculomotor nuclear complex innervates (ipsilateral/contralateral) superior rectus

A

Contralateral

36
Q

Oculomotor nuclear complex innervates (ipsilateral/contralateral) inferior rectus

A

Ipsilateral

37
Q

Oculomotor nuclear complex innervates (ipsilateral/contralateral) inferior oblique

A

Ipsilateral

38
Q

Oculomotor nuclear complex innervates (ipsilateral/contralateral) medial rectus

A

ipsilateral

39
Q

Oculomotor nuclear complex innervates levator palpebrae superioris via ____

A

central caudal nucleus

40
Q

Trochlear nucleus located in:

A

midbrain

41
Q

Trochlear nucleus innervates (ipsilateral/contralateral) _____

A

Contralateral superior oblique

42
Q

Abducens nucleus located in:

A

pons, close to midline beneath floor of 4th ventricle

43
Q

Abducens nucleus innervates (ipsilateral/contralateral) ____

A

Ipsilateral lateral rectus

44
Q

Lesion to abducens nerve results in:

A

palsy of ipsilateral lateral rectus m. –> affected side fails to abduct on horizontal conjugate gaze to that side

45
Q

Lesion of abducens nucleus causes damage to ____ and ____

Leading to ____

A

Lateral rectus motor neurons AND internuclear neurons to contralateral MLF innervating medial rectus

Horizontal conjugate gaze palsy

46
Q

Trochlear nucleus located in:

Path of axons:

A

midbrain at level of inferior colliculus

Dorsalateral and caudal –> superior medullary velum –> CROSS –> dorsal surface, just caudal to inferior colliculi

47
Q

When eye is adducted, superior oblique acts to ____

A

depress the eye

48
Q

When eye is abducted, superior oblique acts to ____

A

intort the eye

49
Q

Trochlear nerve lesion results in ____

Signs:

A

paralysis of ipsilateral superior oblique m

Double vision when looking down and medially –> Compensate for extorsion by tilting head towards non-lesioned side
Vertical diplopia when unaffected eye depressed –> tuck chin and tilt forward –> Pathetic look

50
Q

Lesion of trochlear nucleus produce (ipsilateral/contralateral) signs

A

Contralateral

51
Q

Lesion of trochlear nerve produce (ipsilateral/contralateral) signs

A

Ipsilateral

52
Q

Oculomotor nuclear complex located in:

A

midbrain at level of superior colliculus

53
Q

Lesion of CN3 nucleus OR nerve results in ____

A

down and out syndrome

54
Q

Down and Out Syndrome

Symptoms: (4)

A
  1. Ipsilateral lateral strabismus and depression: eyes do not line up in same direction
  2. Ipsilateral ptosis: loss of levator palpebrae superioris
  3. Ipsilateral mydriasis (dilated pupil) : loss of constrictor pupillae
  4. Loss of direct and consensual pupillary light reflexes in ipsilateral eye
55
Q

Internuclear ophthalmoplegia results from:

A

Lesion to MLF

Ipsilateral adducting eye cannot turn medially, but contralateral eye can but shows NYSTAGMUS

56
Q

Vertical conjugate gaze controlled by:

A

Vertical conjugate gaze center in rostral midbrain

57
Q

Lesions to dorsal midbrain lead to ____

A

paralysis of vertical gaze

58
Q

Parinaud’s Syndrome

A

Eyelid contraction and pupillary deficits

Paralysis of upward gaze (prominent)

59
Q

Nucleus ambiguus location:

Innervation:

A

Medulla

Mm. of pharynx, larynx, soft palate, upper esophagus via CN 10 and 9

60
Q

Lesions of nucleus ambiguus result in:

A

Dysphagia: atrophy and flaccid paralysis of mm. of soft palate, pharynx and larynx
Dysarthria: Flaccid vocal chord

61
Q

Facial nucleus innervates:

A

Mm. of facial expression
Stylohyoid
Posterior digastric
Stapedius

62
Q

Lesions of abducens nucleus often damage ___ also

A

CN7 Facial nerve fibers

63
Q

LMN lesions to facial nerve result in:

A

Facial hemiplegia

64
Q

LMN lesions to facial nucleus result in:

A

Facial hemiplegia

Hyperacusis (sensitivity to loud sounds): loss of inntervation of stapedius mm.

65
Q

UMN lesion to facial nucleus results in:

A

lower quadrant palsy b/c neurons innervating upper facial muscles have bilateral innervation

66
Q

Corneal blink reflex
Involves: (2)
Results in:

A

Facial nucleus (motor to orbicularis oculi), rostral spinal trigeminal nucleus

Consensual both eyes blink from unilateral stimulation of cornea

67
Q

Motor nucleus of CN5
Axons carried by:
Innervates:

A

CNV3

Mm. of mastication, tensor tympani, tensor veli palatini, mylohyoid, anterior digastric

68
Q

Outer layers of superior colliculus receive input from:

A

Retina

Cerebral cortex: visual cortex and frontal eye fields

69
Q

Deep layers of superior colliculus receive input from:

A

Inferior colliculus
Spinal nucleus of V
Spinal cord

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