Neuromotor System Flashcards by Shirley Yancey

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

Jumbled together in middle

Rate of change (velocity) of muscle length

How well did you know this?

Not at all

Perfectly

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

Aligned in single row

Static length of muscle

How well did you know this?

Not at all

Perfectly

Spindle afferents that only innervate nuclear chain fibers

Type II

Signal muscle immediate length

How well did you know this?

Not at all

Perfectly

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

Type 1a

Signal both muscle length an velocity

How well did you know this?

Not at all

Perfectly

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

Gamma motor neurons

Reticulospinal, vestibulospinal

How well did you know this?

Not at all

Perfectly

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

Cerebellum

How well did you know this?

Not at all

Perfectly

Contractile force of motor unit =

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

How well did you know this?

Not at all

Perfectly

Dorsal groups of motor neurons innervate ___

flexors

How well did you know this?

Not at all

Perfectly

Ventral groups of motor neurons innervate ___

Extensors

How well did you know this?

Not at all

Perfectly

Medial groups of motor neurons innervate ____

axial (proximal) muscles

How well did you know this?

Not at all

Perfectly

Lateral groups motor neurons innervate ____

Distal muscles

How well did you know this?

Not at all

Perfectly

Lateral dorsal groups motor neurons innervate ___

most distal muscles (hands)

How well did you know this?

Not at all

Perfectly

5 main descending motor systems

Corticospinal
Corticobulbar
Reticulspinal
Vestibulospinal
Tectospinal 
(Rubrospinal) unimportant

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

Input of central pattern generators

Sensory fibers
Supraspinal neurons (corticospinal system)

How well did you know this?

Not at all

Perfectly

Output of central pattern generators

(mostly inhibitory) alpha and gamma motor neurons

How well did you know this?

Not at all

Perfectly

Intrinsic hand muscle motorneurons are located in _____

Dorsal part of ventral horn at C7-T1

How well did you know this?

Not at all

Perfectly

Lesion of facial nucleus will result in ____

contralateral lower facial hemiparisis

How well did you know this?

Not at all

Perfectly

Major functions of corticobulbospinal tract

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

How well did you know this?

Not at all

Perfectly

Rubrospinal system
Originates in:
Function:

Red nucleus

Facilitate neck and upper limb flexors

How well did you know this?

Not at all

Perfectly

Tract involved in integrating CPG function

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

How well did you know this?

Not at all

Perfectly

Reticulospinal system involved in:

Maintenance of posture
Modulation of muscle tone
CPG coordination

How well did you know this?

Not at all

Perfectly

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

decerebrate rigidity

Lateral vestibulospinal tract’s bias for extension is unopposed

How well did you know this?

Not at all

Perfectly

Tracts that have biased flexion

Rubrospinal

Medullary reticulospinal

How well did you know this?

Not at all

Perfectly

Tracts that have biased extension

Lateral vestibulospinal tract | Pontine reticulospinal tract

Functions of vestibulospinal tract and tectospinal tract

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

Central control on motor system: planning and preparation

Frontal lobe

Central control of motor system: motor or procedural learning

basal ganglia

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

Cerebellum

``` 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)

Supplementary motor areas (SMA) involved in ____

Internally generated movements

Lesion of lateral corticospinal tract in spinal cord produce ____

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

Lesion of corticospinal tract occurring above pyramidal decussation will cause _____

CONTRALATERAL paralysis/paresis

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

Oculomotor nuclear complex located in:

midbrain

Oculomotor nuclear complex innervates (ipsilateral/contralateral) superior rectus

Contralateral

Oculomotor nuclear complex innervates (ipsilateral/contralateral) inferior rectus

Ipsilateral

Oculomotor nuclear complex innervates (ipsilateral/contralateral) inferior oblique

Ipsilateral

Oculomotor nuclear complex innervates (ipsilateral/contralateral) medial rectus

ipsilateral

Oculomotor nuclear complex innervates levator palpebrae superioris via ____

central caudal nucleus

Trochlear nucleus located in:

midbrain

Trochlear nucleus innervates (ipsilateral/contralateral) _____

Contralateral superior oblique

Abducens nucleus located in:

pons, close to midline beneath floor of 4th ventricle

Abducens nucleus innervates (ipsilateral/contralateral) ____

Ipsilateral lateral rectus

Lesion to abducens nerve results in:

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

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

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

When eye is adducted, superior oblique acts to ____

depress the eye

When eye is abducted, superior oblique acts to ____

intort the eye

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

Lesion of trochlear nucleus produce (ipsilateral/contralateral) signs

Contralateral

Lesion of trochlear nerve produce (ipsilateral/contralateral) signs

Ipsilateral

Oculomotor nuclear complex located in:

midbrain at level of superior colliculus

Lesion of CN3 nucleus OR nerve results in ____

down and out syndrome

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

Internuclear ophthalmoplegia results from:

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

Vertical conjugate gaze controlled by:

Vertical conjugate gaze center in rostral midbrain

Lesions to dorsal midbrain lead to ____

paralysis of vertical gaze

Parinaud's Syndrome

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

Nucleus ambiguus location: | Innervation:

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

Lesions of nucleus ambiguus result in:

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

Facial nucleus innervates:

Mm. of facial expression Stylohyoid Posterior digastric Stapedius

Lesions of abducens nucleus often damage ___ also

CN7 Facial nerve fibers

LMN lesions to facial nerve result in:

Facial hemiplegia

LMN lesions to facial nucleus result in:

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

UMN lesion to facial nucleus results in:

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

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

Motor nucleus of CN5 Axons carried by: Innervates:

CNV3 Mm. of mastication, tensor tympani, tensor veli palatini, mylohyoid, anterior digastric

Outer layers of superior colliculus receive input from:

Retina | Cerebral cortex: visual cortex and frontal eye fields

Deep layers of superior colliculus receive input from:

Inferior colliculus Spinal nucleus of V Spinal cord

Neuromotor System Flashcards

(70 cards)