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What is the function, type, deficit, and test of olfactory nerve (I)?
- Function: Smell
- Type: Sensory
- Deficit: Unilateral anosmia
- Test: Odor categories, test ipsilaterally
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What are the function, type, deficit, and test for Optic Nerve (II)?
- Function: Visual acuity
- Type: Sensory
- Deficit: Visual loss
- Test: Snellen chart, test one eye at a time
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Where are the primary neurons for the optic projections?
Retinas
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Where do most of the fibers of the optic projections travel?
Lateral geniculate nucleus of the Thalamus
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Tertiary neurons within the LGN go to where?
The primary visual cortex in the calcarine sulcus via the geniculocalcarine tract
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Visual information that reaches the temporal field is sent to the _______ part of the occipital lobe
Ipsilateral
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Visual information that reaches the nasal field is sent to the ______ part of the occipital lobe
contralateral
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When someone suffers from ipsilateral blindness, where is the lesion?
On the optic nerve
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What does ipsilateral blindness result in?
complete loss of vision in ipsilateral eye
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In bitemporal hemianopsia, where is the lesion?
at the mid-chiasm?
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What loss comes with bitemporal hemianopsia?
Loss of peripheral vision bilaterally (tunnel vision)
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Where is the lesion in right nasa field cut?
Lesion to right temporal projections from retina at the chiasm level
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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
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What area is lesioned to cause homonymous superior quadrantaopsia?
Lesion to Meyer's Loop, beyond the Thalamus
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What is the function, type, deficit, and test of the Occulomotor Nerve (CN III)?
- Function: Moves eye, constricts pupil, accommodates lens, opens eye lid
- Type: Motor
- Deficit: Eye deviates down and out, dilated pupil, ptosis, diplopia
- Test: Planes of gaze, pupillary reactivity
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What is Nystagmus?
Oscillating, conjugate movement
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What is VOR?
- Vestibulo-Ocular Reflex
- Moves eyes to compensate for head movement. Involves semicircular canals, vestibular nuclei and motor nuclei of eyes
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What are the Afferent and Efferent nerves of the Vestibulo-Occular Reflex?
- Afferent: CN VIII
- Efferent: CN III, IV, VI
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What is in charge of the Visceral Motor Component of CN III?
Edinger-Westphal nucleus in the midbrain
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What are the afferent and efferent limbs in the pupillary light reflex?
- Afferent: CN II
- Efferent: CN III
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What is the Accommodation Reflex?
Increase in lens curvature and pupillary restriction for near vision
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What is Strabismus?
Inability to direct both eyes towards the same object and consequent diplopia
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What is Ptosis?
- Eyelid droop
- Dilation of pupil
- Downward abducted eye
- Paralysis of accommodation
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What are two types of Oculomotor Opthalmoplegia (LMN lesions)?
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What is the function, type, deficit, and test of the Trochlear Nerve (CN IV)?
- Function: Moves eye DOWN and out
- Type: Motor
- Deficit: Eye deviates up, diplopia, head tilt
- Test: Down and IN (when eye adducted only SO depresses)
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What is Trochlear Nerve Palsy and how does it present?
- Acquired and congenital
- Compensatory Head Tilt (contralateral)
- Hypertropia - vertical strabisimus
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What is the function, type, deficit, and test for Trigeminal Nerve (CN V)?
- Function: Sensation to face, dura, muscles of mastication
- Type: Sensory/motor
- Deficit: Facial numbness, loss of corneal blink, weak bite
- Test:
- -Sensory: Facial sensation, corneal reflex
- -Motor: Close jaw against resistance
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What are the three branches of CN V and where do they go?
- V1: eye, forehead, orbit
- V2: Upper jaw, mid face, nose
- V3: Low jaw, ear, lips, tongue
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Where is the motor nucleus of CN V?
Tegmentum of pons
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Descrive the function, type, deficit, and test of Abducens Nerve (CN VI)
- Function: Move eye laterally (lateral rectus)
- Type: Motor
- Deficit: Eye deviated inwards, horizontal diplopia
- Test: Planes of gaze: abduction
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What is the function, type, deficit, and test of Facial Nerve (CN VII)?
- Function: Facial expression, lachrymal and salivary glands, stapedius, taste anterior 2/3 of tongue, sensation to external ear
- Type: Sensory/motor
- Deficit: Facial weakness, eye closure weakness, hyperacusis, loss of taste anterior 2/3 of tongue
- Test: Smile, wrinkle forehead
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What are the 4 components of CN VII?
- Branchial motor
- Visceral motor
- General sensory
- Special sensory
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Where does CN VII emerge?
From brainstem at pontomedullary border
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CN VII UMN innervation of the face is _______ and the mouth is _______
bilateral; contralateral
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What is Bell's Palsy?
- LMN lesion to CN VII
- Damage to facial nucleus or its axons anywhere along the course of the nerve
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What are the reflexes for CN VII?
- Blink Reflex
- Acousting (Stapedius) Reflex
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What are the afferents and efferents to the blink reflex?
- Afferent: CN II (light), CN V (touch), CN VIII (loud noise)
- Efferent: CN VII (Blink)
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What is the afferent and efferent to the acoustic reflex?
- Afferent: cochlear component of CN VIII
- Efferent: CN VII contraction of stapedius
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