Neuro Lecture 6
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Neuro Lecture 6
What is the function, type, deficit, and test of olfactory nerve (I)?
: Unilateral anosmia
: Odor categories, test ipsilaterally
What are the function, type, deficit, and test for Optic Nerve (II)?
: Visual acuity
: Visual loss
: Snellen chart, test one eye at a time
Where are the primary neurons for the optic projections?
Where do most of the fibers of the optic projections travel?
Lateral geniculate nucleus of the Thalamus
Tertiary neurons within the LGN go to where?
The primary visual cortex in the calcarine sulcus via the geniculocalcarine tract
Visual information that reaches the temporal field is sent to the _______ part of the occipital lobe
Visual information that reaches the nasal field is sent to the ______ part of the occipital lobe
When someone suffers from ipsilateral blindness, where is the lesion?
On the optic nerve
What does ipsilateral blindness result in?
complete loss of vision in ipsilateral eye
In bitemporal hemianopsia, where is the lesion?
at the mid-chiasm?
What loss comes with bitemporal hemianopsia?
Loss of peripheral vision bilaterally (tunnel vision)
Where is the lesion in right nasa field cut?
Lesion to right temporal projections from retina at the chiasm level
What is Homonymous Hemianopsia and where does the lesion occur to bring about this condition?
Complete loss of vision in opposite half of visual field
Damage to optic tract
What area is lesioned to cause homonymous superior quadrantaopsia?
Lesion to Meyer's Loop, beyond the Thalamus
What is the function, type, deficit, and test of the Occulomotor Nerve (CN III)?
: Moves eye, constricts pupil, accommodates lens, opens eye lid
: Eye deviates down and out, dilated pupil, ptosis, diplopia
: Planes of gaze, pupillary reactivity
What is Nystagmus?
Oscillating, conjugate movement
What is VOR?
Moves eyes to compensate for head movement. Involves semicircular canals, vestibular nuclei and motor nuclei of eyes
What are the Afferent and Efferent nerves of the Vestibulo-Occular Reflex?
: CN VIII
: CN III, IV, VI
What is in charge of the Visceral Motor Component of CN III?
Edinger-Westphal nucleus in the midbrain
What are the afferent and efferent limbs in the pupillary light reflex?
: CN II
: CN III
What is the Accommodation Reflex?
Increase in lens curvature and pupillary restriction for near vision
What is Strabismus?
Inability to direct both eyes towards the same object and consequent diplopia
What is Ptosis?
Dilation of pupil
Downward abducted eye
Paralysis of accommodation
What are two types of Oculomotor Opthalmoplegia (LMN lesions)?
What is the function, type, deficit, and test of the Trochlear Nerve (CN IV)?
: Moves eye DOWN and out
: Eye deviates up, diplopia, head tilt
: Down and IN (when eye adducted only SO depresses)
What is Trochlear Nerve Palsy and how does it present?
Acquired and congenital
Compensatory Head Tilt (contralateral)
Hypertropia - vertical strabisimus
What is the function, type, deficit, and test for Trigeminal Nerve (CN V)?
: Sensation to face, dura, muscles of mastication
: Facial numbness, loss of corneal blink, weak bite
: Facial sensation, corneal reflex
: Close jaw against resistance
What are the three branches of CN V and where do they go?
: eye, forehead, orbit
: Upper jaw, mid face, nose
: Low jaw, ear, lips, tongue
Where is the motor nucleus of CN V?
Tegmentum of pons
Descrive the function, type, deficit, and test of Abducens Nerve (CN VI)
: Move eye laterally (lateral rectus)
: Eye deviated inwards, horizontal diplopia
: Planes of gaze: abduction
What is the function, type, deficit, and test of Facial Nerve (CN VII)?
: Facial expression, lachrymal and salivary glands, stapedius, taste anterior 2/3 of tongue, sensation to external ear
: Facial weakness, eye closure weakness, hyperacusis, loss of taste anterior 2/3 of tongue
: Smile, wrinkle forehead
What are the 4 components of CN VII?
Where does CN VII emerge?
From brainstem at pontomedullary border
CN VII UMN innervation of the face is _______ and the mouth is _______
What is Bell's Palsy?
LMN lesion to CN VII
Damage to facial nucleus or its axons anywhere along the course of the nerve
What are the reflexes for CN VII?
Acousting (Stapedius) Reflex
What are the afferents and efferents to the blink reflex?
: CN II (light), CN V (touch), CN VIII (loud noise)
: CN VII (Blink)
What is the afferent and efferent to the acoustic reflex?
: cochlear component of CN VIII
: CN VII contraction of stapedius