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75 Cards in this Set
- Front
- Back
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what fibers cross at the optic chiasm
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Nasal fibers
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what fibers do the optic tract contain
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ipsilateral Temporal retina
contralateral Nasal retina axons and information from both eyes |
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where is the primary visual cortex located
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brodmann's area 17
surrounds Calcarine Fissure on the medial surface of the Occipital Lobe |
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what is the LINGUAL gyrus and what is the path leading to it
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superior visual field
inferior retina LGN TEMPORAL LOBE lingual gyrus |
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what is the CUNEUS gyrus and what is the path leading to it
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inferior visual field
superior retina LGN PARIETAL LOBE cuneus gyrus |
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right optic nerve lesion will result in...
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monocular blindness (OD)
APD (OD) |
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optic chiasm lesion at midline will result in...
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bitemporal hemianopia (peripheral vision loss)
destroys crossing nasal fibers major cause: pituitary gland tumor aneurysm in anterior cerebral or anterior communicating artery |
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right lateral margin of optic chiasm lesion will result in...
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nasal hemianopia (OD)
major cause: aneurysm or atherosclerosis of ICA |
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right optic tract lesion will result in...
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left homonymous hemianopia
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lesion of what will result in a RIGHT HOMONYMOUS HEMIANOPIA
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right optic tract
right LGN ALL visual radiation entire right side of primary visual cortex right internal capsule |
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lesion in OD visual radiation fibers in Meyer's loop pathway will result in
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left superior homonymous quadrantanopia
due to lesion of temporal lobe, enlargement of lateral ventricle tumors |
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lesions to visual radiation fibers running through parietal lobe will result in...
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left inferior homonymous quadrantanopia
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lesion in right primary visual cortex will result in...
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left homonymous hemianopia
left homonymous hemianopia with macular sparring major cause: posterior cerebral artery damage |
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what causes macular sparing in right primary visual cortex lesions
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collateral circulation of middle cerebral artery
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what common with a blow to the back of the head
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bilateral central scotoma
loss of macular vision |
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which artery supplies blood to the primary visual cortex
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POSTERIOR CEREBRAL ARTERY
CALCARINE BRANCHES collateral circulation from MIDDLE CEREBRAL ARTERY in case of occlusion of posterior cerebral arteries |
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what is the corticospinal tract
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precentral gyrus
internal capsule crus cerebri through pyramids Lateral Corticospinal Tract cross at caudal medulla (85%) Ventral Corticospinal Tract cross at level of the spinal cord (15%) |
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what are the 5 extrapyramidal upper motor neurons (contra, ips, or bi)
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Rubrospinal (contra)
Pontine Reticulospinal (ipsi) Medullary Reticulospinal (ipsi) Lateral Vestibulospinal (ipsi) Medial Vestibulospinal (bi) |
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what is the corpus striatum
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1.caudate nucleus
2.putamen 3.globus pallidus (1&2=striatum) (2&3)=lenticular nucleus |
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degeneration of the...results in Parkinson's Disease
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substantia nigra
*largest nucleus in the midbrain |
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what is the main circuit of the basal ganglia
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Cerebral cortex
Striatum Globus Pallidus Thalamus *back to the Cerebral Cortex |
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how does the basal ganglia contribute to the motor control
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basal ganglia DO NOT directly affect the motor neurons
basal ganglia influence motor control INDIRECTLY by modifying the output of the descending fibers from the cerebral cortex |
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what is the main circuit of the basal ganglia
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Cerebral cortex
Striatum Globus Pallidus Thalamus *back to the Cerebral Cortex |
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how does the basal ganglia contribute to the motor control
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basal ganglia DO NOT directly affect the motor neurons
basal ganglia influence motor control INDIRECTLY by modifying the output of the descending fibers from the cerebral cortex |
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what is the pathway of the cerebellum
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1. fibers from SC and brainstem enter and synapse in both cerebellar deep nuclei and cerebellar cortex
2. Purkinje cells in the cortex send axons to the deep nuclei, modulating the output of the nuclei 3. deep nuclei send fibers out of the cerebellum to the brainstem and thalamus |
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how does the basal ganglia inhibit movement
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putamen
GP (external) subthalamus GP (internal) |
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what pathway does the basal ganglia take to facilitate movement
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putamen
GP (internal) and substantia nigra |
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progressive supranuclear palsy
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associated with parkinson's
supranuclear ophthalmoplegia (downward gaze paresis, spreads to other eye muscles) |
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C&S Huntington's Chorea
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C: autosomal dominant movement disorder, mid 30s
chromosome 4 S: chorea dementia impaired saccades |
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Wilson's disease
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C: autosomal recessive movement disorder
chromosome 13 copper metabolism defect kayser-fleischer ring on outer margin of cornea |
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acoustic neuroma
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CN VIII tumor
damage to cerebellopontine angle or internal acoustic meatus unilateral hearing loss and tinnitus (ringing/buzzing) facial weakness/loss of corneal reflex ipsilateral loss of pain and temp. |
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what are the two components of the vestibulocochlear nerve (CN VIII)
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auditory: from cochlea
vestibular: balance from semicircular canals |
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what acts as proprioceptors in ear and where are they located
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hair cells
1.macula uticuli/macula sacculi (linear/posture) 2.cristae amullaris (angular/maintains balance) |
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what is the difference between nerve and conductive deafness
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1. conductive: physical obstruction of sound waves from getting into the ear (inflammation, foreign body, ear wax, etc)
2. disease of cochlea (hair cells), cochlear nerve (acoustic neuroma), cochlear nuclei in the medulla (unilateral damage to the peripheral portion results in significant IPSILATERAL hearing loss) |
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what is the degree of hearing loss with a central portion? why?
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minor hearing loss
pass the cochlear nuclei the information ascends BILATERALLY to the cortex difficulty in locating direction of the source of sounds and in understanding speech in areas of high background noise. |
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auditory pathway (peripheral portion)
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external ear
external auditory meatus tympanic membrane middle ear bony ossicles inner ear fluid organ of corti (hair cells) cochlear division (CN VIII) cochlear nuclei in rostral medulla |
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auditory pathway (central portion)
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after bifurcation @ cochlear nucleus
lateral lemniscus (X and unX) inferior colliculus (midbrain) inferior brachium (axons of inf. colliculus) MGN of thalamus auditory radiation (axons MGN) transverse termporal gyrus in temporal lobe (41,42) |
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what is the difference between nerve and conductive deafness
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1. conductive: physical obstruction of sound waves from getting into the ear (inflammation, foreign body, ear wax, etc)
2. disease of cochlea (hair cells), cochlear nerve (acoustic neuroma), cochlear nuclei in the medulla (unilateral damage to the peripheral portion results in significant IPSILATERAL hearing loss) |
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what is the degree of hearing loss with a central portion? why?
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minor hearing loss
pass the cochlear nuclei the information ascends BILATERALLY to the cortex difficulty in locating direction of the source of sounds and in understanding speech in areas of high background noise. |
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auditory pathway (peripheral portion)
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external ear
external auditory meatus tympanic membrane middle ear bony ossicles inner ear fluid organ of corti (hair cells) cochlear division (CN VIII) cochlear nuclei in rostral medulla |
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auditory pathway (central portion)
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after bifurcation @ cochlear nucleus
lateral lemniscus (X and unX) inferior colliculus (midbrain) inferior brachium (axons of inf. colliculus) MGN of thalamus auditory radiation (axons MGN) transverse termporal gyrus in temporal lobe (41,42) |
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rinne's test
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stem of tuning fork held at mastoid process until no longer heard, then held in from of ear.
normal: AC better than BC (but hears both) conductive: BC better than AC nerve: AC better than BC in impaired ear |
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weber's test
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stem of tuning fork held at vertex of the head, ask patient which ear is better
Normal: EQUAL Conductive: better in ear with heading deficit Nerve: better in ear w/o hearing deficit |
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where is the first synapse of the olfactory system
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OLFACTORY BULB
NOT THALAMUS!!!! IPSILATERAL |
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olfactory pathway
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olfactory mucosa (chemoreceptors)
CN I olfactory bulb olfactory tract then splits to: lateral olfactory area (primary olfactory cortex, entorhinal cortex, amygala) medial olfactory area: septal area connected by anterior commissure |
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what is the two halves of the olfactory pathway connected by
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anterior commissure
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what is olfactory hallucinations? anosmia?
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1.seizures of the temporal lobe
lesions near the lateral olfactory area (uncus, entorhinal cortex, amygdala) 2. loss of smell (head injuries damage CN I) |
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ossicles consist of
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malleus
incus stapes |
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chorea
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rapid, jerky movements
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athetosis
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slow, writhing movements, snake-like
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dystonia
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slow, sustaining contractions of head and trunk
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ballism
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violent flinging movements of limbs
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input/output to the cerebrocerebellum (motor planning)
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input: contralateral cerebral cortex, indirectly via the pons
output: (contralateral) red nucleus projects to thalamus, (contralateral) thalamus relays to to cortex |
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CEREBELLUM controls the ... side of the body whereas the CEREBRAL CORTEX controls the ... side of the body
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Cerebellum: IPSILATERAL
Cerebral Cortex: contralateral |
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tonsils of the cerebellum can herniate through which foramen?
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MAGNUM FORAMEN
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Arnold-Chiari Phenomenon
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1.blockage of the flow of CSF from 4th ventricle...hydrocephlus
2.spina bifida 3.pressure on cerebellum and medulla oblongata (CN 9,10,11,12) |
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basal ganglia disorders v.s. cerebellar disorders (in respects to movement)
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BG: UNintentional
Cerebellar: INTENTIONAL |
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vestibular nuclei projects to...via which pathway
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1.cerebellum: direct
2.cerebral cortex: vestibulothalamic tract 3.spinal cord: lateral (ipsi) & medial (bi) vestibulospinal 4.gaze center and OMN: ascending portion of MLF |
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what are the symptoms of damaged vestibular system
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1.vertigo: whirling surroundings
2.nystagmus: twitch of eye 3.loss of balance |
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doll's eye phenomenon
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testing the integrity of the VESTIBULO-OCULAR REFLEX in an UNCONSCIOUS patient.
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caloric test
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integrity of the vestibular system can be assessed by triggering a nystagmus (head angled 30 degrees)
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what are the subdivisions of the MIDBRAIN
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1.Tectum (superior/inferior colliculus)
2.Cerebral Peduncle (tegmentum, substantia nigra, crus cerebri) 3.Cerebral Aqueduct |
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what nucleuses are associated with the midbrain
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edinger-westphal (behind o.motor)
oculomotor (s. colliculus) trochlear (inf. colliculus) |
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weber's syndrome
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alternating oculomotor hemiplegia
damage to ipsilateral CN3 and contralateral Pyramidal Tract cause: aneurysm of posterior cerebral antery |
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lateral gaze center
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located in the abducens nucleus in the pons
1.LMN portion of the abducens nucleus innervates IPSI lateral rectus 2.Interneuron portion via axons travel in MLF activate contralateral O.Motor nucleus to Medial Rectus |
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internuclear ophthalmoplegia
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damage: bilateral to the MLF
1.inability to adduct eye during lateral gaze to either side 2.Nystagmus |
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Parinaud's Syndrome
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damage: compression of dorsal midbrain near the vertical gaze center
cause: pinealoma inability to raise eyes above the horizontal plane |
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Pupillary Light Reflex Pathway
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light
retina optic nerve optic chiasm optic tract PRETECTAL NUCLEI BOTH Edinger-Westphal Nuclei Preganglionic Parasympathetic nerve fibers in CN3 Ciliary Ganglia Postganglionic parasympathetic nerve fibers Sphincter pupillae muscles CONSTRICTION |
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Argyll-Robertson pupil
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Pupil: NO CONSTRICTION w/ Light
bilateral damage of pretectal area (syphilis) pupils CAN constrict during ACCOMODATION (different pathway) |
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Accomodation of the EYE (PATHWAY)
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Near Object
Retina Optic Nerve Optic Chiasm Optic Tract Lateral Geniculate Body Optic Radiation Visual Cortex Edinger-Westphal Ciliary Ganglion CONSTRICTION |
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what is the largest projection to the HYPOTHALAMUS
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FORNIX
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what is the most common site for a stroke
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internal capsule
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what pathway corresponds with the suprachiasmatic nucleus
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retinohypothalamic tract
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which stages of sleep are the most restorative
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3 and 4
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what is part of the hippocampal formation? regeneration?
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dentate gyrus*
subiculum hippocampus *regenerate |
