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Flashcards in Neuromotor System Deck (70):
0

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

Aligned in single row
Static length of muscle

1

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

Jumbled together in middle
Rate of change (velocity) of muscle length

2

Spindle afferents that only innervate nuclear chain fibers

Type II
Signal muscle immediate length

3

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

Type 1a
Signal both muscle length an velocity

4

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

Gamma motor neurons
Reticulospinal, vestibulospinal

5

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

Cerebellum

6

Contractile force of motor unit =

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

7

Dorsal groups of motor neurons innervate ___

flexors

8

Ventral groups of motor neurons innervate ___

Extensors

9

Medial groups of motor neurons innervate ____

axial (proximal) muscles

10

Lateral groups motor neurons innervate ____

Distal muscles

11

Lateral dorsal groups motor neurons innervate ___

most distal muscles (hands)

12

5 main descending motor systems

Corticospinal
Corticobulbar
Reticulspinal
Vestibulospinal
Tectospinal
(Rubrospinal) unimportant

13

Project their axons across different levels of cord.
Yoke together proprioceptive systems and alpha/gamma motor neurons in networks called ____

Propriospinal interneurons in intermediate zone
Central pattern generators

14

Input of central pattern generators

Sensory fibers
Supraspinal neurons (corticospinal system)

15

Output of central pattern generators

(mostly inhibitory) alpha and gamma motor neurons

16

Intrinsic hand muscle motorneurons are located in _____

Dorsal part of ventral horn at C7-T1

17

Lesion of facial nucleus will result in ____

contralateral lower facial hemiparisis

18

Major functions of corticobulbospinal tract

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

19

Rubrospinal system
Originates in:
Function:

Red nucleus
Facilitate neck and upper limb flexors

20

Tract involved in integrating CPG function

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

21

Reticulospinal system involved in:

Maintenance of posture
Modulation of muscle tone
CPG coordination

22

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

decerebrate rigidity
Lateral vestibulospinal tract's bias for extension is unopposed

23

Tracts that have biased flexion

Rubrospinal
Medullary reticulospinal

24

Tracts that have biased extension

Lateral vestibulospinal tract
Pontine reticulospinal tract

25

Functions of vestibulospinal tract and tectospinal tract

Postural control through facilitation of extensors
Coordination of head, neck and axial spine movements

26

Central control on motor system: planning and preparation

Frontal lobe

27

Central control of motor system: motor or procedural learning

basal ganglia

28

Central control of motor system: hitting the target
Accuracy and sequencing of complex voluntary movements

Cerebellum

29

Premotor area (PMA) involved in ______
Represents:

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

30

Supplementary motor areas (SMA) involved in ____

Internally generated movements

31

Lesion of lateral corticospinal tract in spinal cord produce ____

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

32

Lesion of corticospinal tract occurring above pyramidal decussation will cause _____

CONTRALATERAL paralysis/paresis

33

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

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

34

Oculomotor nuclear complex located in:

midbrain

35

Oculomotor nuclear complex innervates (ipsilateral/contralateral) superior rectus

Contralateral

36

Oculomotor nuclear complex innervates (ipsilateral/contralateral) inferior rectus

Ipsilateral

37

Oculomotor nuclear complex innervates (ipsilateral/contralateral) inferior oblique

Ipsilateral

38

Oculomotor nuclear complex innervates (ipsilateral/contralateral) medial rectus

ipsilateral

39

Oculomotor nuclear complex innervates levator palpebrae superioris via ____

central caudal nucleus

40

Trochlear nucleus located in:

midbrain

41

Trochlear nucleus innervates (ipsilateral/contralateral) _____

Contralateral superior oblique

42

Abducens nucleus located in:

pons, close to midline beneath floor of 4th ventricle

43

Abducens nucleus innervates (ipsilateral/contralateral) ____

Ipsilateral lateral rectus

44

Lesion to abducens nerve results in:

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

45

Lesion of abducens nucleus causes damage to ____ and ____
Leading to ____

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

Horizontal conjugate gaze palsy

46

Trochlear nucleus located in:
Path of axons:

midbrain at level of inferior colliculus

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

47

When eye is adducted, superior oblique acts to ____

depress the eye

48

When eye is abducted, superior oblique acts to ____

intort the eye

49

Trochlear nerve lesion results in ____
Signs:

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

Lesion of trochlear nucleus produce (ipsilateral/contralateral) signs

Contralateral

51

Lesion of trochlear nerve produce (ipsilateral/contralateral) signs

Ipsilateral

52

Oculomotor nuclear complex located in:

midbrain at level of superior colliculus

53

Lesion of CN3 nucleus OR nerve results in ____

down and out syndrome

54

Down and Out Syndrome
Symptoms: (4)

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

Internuclear ophthalmoplegia results from:

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

56

Vertical conjugate gaze controlled by:

Vertical conjugate gaze center in rostral midbrain

57

Lesions to dorsal midbrain lead to ____

paralysis of vertical gaze

58

Parinaud's Syndrome

Eyelid contraction and pupillary deficits
Paralysis of upward gaze (prominent)

59

Nucleus ambiguus location:
Innervation:

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

60

Lesions of nucleus ambiguus result in:

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

61

Facial nucleus innervates:

Mm. of facial expression
Stylohyoid
Posterior digastric
Stapedius

62

Lesions of abducens nucleus often damage ___ also

CN7 Facial nerve fibers

63

LMN lesions to facial nerve result in:

Facial hemiplegia

64

LMN lesions to facial nucleus result in:

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

65

UMN lesion to facial nucleus results in:

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

66

Corneal blink reflex
Involves: (2)
Results in:

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

Consensual both eyes blink from unilateral stimulation of cornea

67

Motor nucleus of CN5
Axons carried by:
Innervates:

CNV3

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

68

Outer layers of superior colliculus receive input from:

Retina
Cerebral cortex: visual cortex and frontal eye fields

69

Deep layers of superior colliculus receive input from:

Inferior colliculus
Spinal nucleus of V
Spinal cord