Lecture 7 Flashcards by Hailey jackson

Anterior corticospinal tract primarily controls _______

axial musckes (neck and trunk), controls muscles bilaterally

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Describe charcterics of anterior coticospinal tract

May divide and cross at spinal level

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Identify this pathway

anterior corticospinal tract

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Describe pathway of anterior corticospinal tract

descends ipsilaterally in anterior column as get to innervated level in SC, may bifurfacate. One side stays ipsilateral and other crosses midlone in white matter (commisural fibers) to activate cell bodies on opposite side

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From anterior column, anterior corticospinal tract enter ___

anterior horn

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Identify this structure

Internal capsule

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Identify this structure

Medulla

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Identify this structure

anterior corticospinal tract

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Identify this structure

lateral corticospinal tract

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Identify this structure

lower motor neuron

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Site of origin of anterior corticospinal tract

primary motor cortex and supplementary area

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level of termination of anterior corticospinal tract

cervical and upper thoracic cord

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function of anterior corticospinal tract

control of bilateral axial and girdle muscles

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Describe upper and lower motor neuron for corticobulbar tract

UMN from facial region synapse with LMN in pons
Lower motor nuclei controlling facial expression called facial nuclei, extends as facial nerve (CN VII).

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Describe cranial nuclei

Within the brainstem 12 nuclei (cranial nuclei), can have motor or sensory function or autonomic function. If motor function exons extend out to muscle, if have sensory have afferent info coming into cranial nerves. Nerves that project out form cranial nuclei (12 cranial nerves).

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Name for cranial nuclei 7

facial nerve

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Name for cranial nerve 7

facial nerve

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Function of facial nerve

Carries motor neurons that travel to muscle of face responsible for face expression

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Facial nerves conisdered like _____

LMN’s, travel from CNS to muscle, same functions as LMN going out from spinal cord out to muscles

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Where facial nuclei found

In the pons (left and right side)

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Muscles of facial expression innervates by

facial nerve

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CN VII travels to ____

ipsilateral facial muscles

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How to upper motor neurons of corticobulbar tract travel

UMN travel bilaterally to CN VII for muscles above the eyes (e.g. foehead)
UMN travel contralaterally to CN VII for muscles below eyes: at pons crosses the midloine act on LMN for lower part of face. No ipsilateral inputs for lower part of face

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Identify this part of cortex

contralateral primary motor cortex

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Identify this part of cortex

ipsilateral primary motro cortex

Identify this

Upper motor neuron

Identify this

pons

Identify this

CN VII

Identify this

Lower motor neuron

Identify this type of injury

Upper motor neuron-type facial weakness

Identify this type of injury

Lower motor neuron-type facial weakness

Weakness on entire side of face (upper and lower neurons)- whats the damage?

Damage to facial nuclei in pons, e.g. with damage to pons on ipsilateral side, or facial nerve (where axons for those muscles are travelling together). Damage on same side as symptoms.

Weakness on lower portion of face (not including upper portions)- whats the damage?

Damage to upper motor neuron e.g. with damage to the cortex or nerve, the LMN remains intact. Some preserved function of upper portions of face because of intact ipsilateral inputs from motor cortex.

Describe facial palsy

unknown origin (viris?), enflamed facial nerve or nucleus, weakness on entire side of face on ipsilateral side of symptoms

Describe organisation of corticospinal and corticobulbar tracts

axons maintain somatotopic organisation

Describe how to test for facial weakness

asking patient to do facial expressions- e.g. squeeze eyes shut or raise eyebrow or smile, gimace

Describe organisation of muscles at level of internal capsule

from anterior to posterior: face, arms, trunks, legs

Describe organisation of muscles at level of midbrain

face most medial, arms, trunk, legs most lateral

Describe what happens with somatotopic organisation of fibres as move down brainstem into spinal cord

As continue from internal capusle to basis pedunculi ribbon of axons rotates, at pons, face gets off, the arms most medial once reach cervical regions, arms which are most medial enter anterior horn, then by the level of the lumbar region, only legs left

Identify the muscles of this region of internal capsule

Leg

Identify the muscles of this region of internal capsule

trunk

Identify the muscles of this region of internal capsule

arm

Identify the muscles of this region of internal capsule

face

Identify the muscles of this region of midbrain

Leg

Identify the muscles of this region of midbrain

trunk

Identify the muscles of this region of midbrain

arm

Identify the muscles of this region of midbrain

face

Identify this muscle

legs and feet

Identify this muscle

trunk

Identify this muscle

arms and hands

Identify this muscle

face

Identify 4 other descending motor tracts that may infleunce lower motor neurons

Rubrospinal tract, reticulospinal tract, vestibulospinal tract. tectospinal tract

where are the origin of other descending tracts

brainstem

Describe rubrospinal tract location

from red nucleus in midbrain to spinal cord

Describe reticoluspinal tract location

from reticular formation (nuclei run through central part of brainstem) to spinal cord

Describe vestibulospinal tract location

from vestibular nuclei to spinal cord

describe tectospinal tract location

from superior colliculus to spinal cord

Identify this

tectum

Identify this

red nucleus

Identify this

medial reticular formation

Identify this

lateral reticular formation

Identify this

lateral and medial vestibular nuclei

Lateral corticospinal tract travels in the _____

lateral column

Site of origin of rubrospinal tract

red nucleus, manocellular division

Site of decussation of rubrospinal tract

ventral tegmental ducussation in midbrain

level of termination of rubrospinal tract

cervical cord

function of rubrospinal tract

movement of the contralateral limbs , faciliates flexor tone and inhibits extensor muscle tone in arms

rubrospinal tract travels in ______

lateral column (primarily to cervical segments)

Identify this tract

rubrospinal tract

Site of origin of vestibulospinal tracts

medial VST: medial and inferior vestibulo nuclei; lateral VST: lateral vestibular nucleus

Nuclei that give rise to vestibular spinal tracts

medial and lateral vestibular nucleus

level of termination of vestibulospinal tract

Medial VST: cervical and upper thoracic cord; lateral VST: entire cord

Function of vestibulospinal tract

medial VST: positioning of the head and neck; lateral VST: balance

Describe lateral vestibulospinal tract location and function

originates from lateral vestibular nucleus at level of pons , ipsilateral to all levels of spinal cord, faciliates extensor muscle tone, inhibition of flexor muscle tone in arms and legs,

Describe medial vestibulospinal tract location and function

orginiates from medial vestibular nuclues in medualla, bi-lateral to cervical and thoracic levels it bifurfactes at level of nucleus, have both reflex and tone activationof axial (trunk) and neck muscles

origin of reticulospinal tracts

pontine and medullary reticular formation

level of termination of reticulospinal tract

entire cord

Function of reticulospinal tract

automatic posture and gait-related movements, **modulates reflexes and tone**

Where reticulospinal tract travels

ventral column to spinal levels (medial motor nuclei)

Tracts treveling in lateral motor systems

lateral corticospinal tract and rubrospinal tract

tracts traveling in medial motor systems

anterior corticospinal tract, lateral vestibulospinal tracts, and pontine reticulospinal tract