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119 Cards in this Set
- Front
- Back
temporal lobe abscess
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causes: staph, strep, bacteroides
cavities usually surrounded by fibroblasts and new vessels pts usually have a predisposing condition ->endocarditis, bronchiectasis |
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tx of OCD
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TCAs (clomipramine)
SSRIs (fluoxetine) |
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which nerve innervates posterior half of external auditory hiatus
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auricular branch of the vagus nerve
-compression can cause symptoms like fainting, coughing, gagging |
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selective frontal and temporal atropy in a demented patient
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suggests Pick disease
severe neuronal loss and astrocytosis pick bodies: intracytoplasmic spherules w/paired helical filaments (SILVER STAIN best) |
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embolization from endocarditis usually affects what part of the brain?
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multiple small parietal lobe abscesses
leads to defect in spatial recognition often mistaken for small strokes |
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notable SEs for lithium
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hypothyroidism, nephrogenic DI, and tremors
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Negri bodies
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pathognomonic for Rabies encephalitis
most often in hippocampus and cerebellar cortex histo: elongated eosinophlilic intracytoplasmic inclusions |
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tumors of lateral ventricle can affect which structure by direct extension
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caudate nucleus [comprises part of the wall of the lateral ventricle]
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Arnold-Chiari type 2
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abnormally small posterior fossa
->downward displacement of cerebellar vermis and medulla thru foramen magnum ->obstruction of CSF flow leads to hydrocephalus |
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Arnold-Chiari type 1
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more common than type 2
downward displacement of cerebellar tonsils thru foramen magnum -> usually asymptomatic, found on autopsy |
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Dandy-Walker malformation
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abnormally large posterior fossa
cerebellar vermis is absent and replaced by a midline cyst [looks like an expanded 4th ventricle] brainstem nuclei are also abnormal |
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Glioblastoma multiforme
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most agressive astrocytic tumor (type IV)
necrosis or hemorrhage on cut section pleiomorphic tumor cells that are frequently bizarre with markedly enlarged, abnormal nuclei adults: cerebral cortex children: brainstem |
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HSV encephalitis
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necrotizing, hemorrhagic acute
lower portions of cerebral cortex: temporal and base of frontal lobes [maybe b/c spreads from oropharynx] |
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60% of brain abscesses are related to _____ infection
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middle ear infection [OM] (especially cerebellar abscesses)
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most common site of obstruction resulting in hydrocephalus
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aqueduct of sylvius
(connects 3rd ventricle to 4th ventricle) |
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normal pressure hydrocephalus
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classic triad
->memory loss ->urinary incontinance ->gait abnormalities results from intermittent increases in CSF pressure, leads to progressive damage to cerebral white matter and dilation of the ventricles Tx: ventricular shunt |
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neurotransmitter that induces REM sleep
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ACh
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marker to determine proliferative activity of astrocytoma
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Ki-67
(also check mitotic activity) |
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superior opthalmic vein communicates directly with
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cavernous sinus
->also contains CN III, IV, VI, V2 and V1, and ICA |
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uncal herniation
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medial aspect of temporal lobe (uncus) is forced under free edge of tentorium cerebelli
often compresses oculomotor nerve (CN III) |
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Kernig's sign
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flex patient's hip but can't extend the knee without causing pain
sign of meningeal irritation (check for bacterial meningitis) |
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two lateral ventricles communicates with the 3rd ventricle thru the ______
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foramen of Monroe
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the _____ connects the 3rd and 4th ventricles
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cerebral aqueduct
blockage results in hydrocephalus |
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4th ventricle communicates with the subarachnoid space through ______
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three outlet foramina:
2 lateral foramina of Luschka medial foramen of Magendie |
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noncommunicating hydrocephalus
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obstruction within the ventricles
[congenital aqueductal stenosis] |
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communicating hydrocephalus
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blockage within the subarachnoid space
[adhesions after meningitis] |
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anterior cerebral artery
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paracentral lobule
->leg-foot motor/sensory ACoA: most common site of circle of Willis aneurysm ->causes bitemporal lower quandrantanopia medial striate arteries: ->supply anterior putamen and caudate and internal capsule |
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middle cerebral artery
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Broca's, Wernicke's, face and arm, frontal eye field
lateral striate arteries ->'stroke' arteries. supply internal capsule, caudate, putamen, globus pallidus |
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vertebral artery
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branch of subclavian. gives rise to anterior spinal and PICA
->PICA supplies nucleus ambiguous (CN 9,10,11) and inferior cerebellum |
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basilar artery
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formed by two vertebral arteries
supplies base of pons (pontine arteries) and CN VI fibers AICA suppplies lateral tegmentum, CN VII, spinal trigeminal tract of CN V, inferior cerebellum |
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posterior cerebral artery
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branch of basilar
connects to carotid via posterior communicating artery **major blood supply to MIDBRAIN also thalamus, lateral/medial geniculate bodies, occipital lobe occlusion = contralateral hemianopia with macular sparing |
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blood supply of internal capsule
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lateral striate arteries (from MCA)
and anterior choroidal artery (arises from ICA. not part of the circle of willis) |
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superior sagittal sinus
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receives bridging veins, and CSF via the arachnoid villi
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cavernous sinus
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contains CN II, IV, V1, V2, VI and post-ganglionic sympathetic fibers
also contains ICA |
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middle meningeal artery
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branch of maxillary artery
enters thru foramen spinosum supplies most of dura laceration = epidural hematoma |
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forebrain [prosencephalon]
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telecephalon -> cerebral hemispheres/lateral ventricles
diencephalon-> thalmaus/ third ventricle |
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midbrain [messencephalon]
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mesencephalon-> midbrain/ aqueduct
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hindbrain [rhombencephalon]
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metencephlon-> pons, cerebellum, upper part of 4th ventricle
myelencephalon-> medulla, lower part of 4th ventricle |
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failure of the _____ to close results in spina bifida
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posterior neuropore
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failure of the _____ to close results in anencephaly
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anterior neuropore
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fast anterograde axonal transport
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transports newly synethesized organelles and NT precursors
mediated by neurotubules and kinesin |
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fast retrograde transport
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returns used materials from axon termina to cell body for degredation/recycling
->nerve growth factor, neurotropic viruses [HSV, rabies, polio, tetanus toxin] mediated by neuortubules and dynein |
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common muscle stretch reflexes
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ankle jerk: S1-> gastrocnemius
knee jerk: L2-L4-> quadriceps biceps jerk: C5-C6-> biceps forearm jerk: C5-C6-> brachioradialis triceps jerk: C7-C8-> triceps |
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dorsal column/medial lemniscus pathway
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tactile discrimination, vibration, form recognition, proprioception
1st order: dorsal root ganglia ->gracile fasciculus (lower) ->cuneate fasciculus (upper) 2nd order: dessucate at caudal medulla, form medial lemniscus-> terminates in VPL of thalamus 3rd order: VPL. project to primary somatosensory cortex (areas 3,1,2) |
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lateral spinothalamic tract
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pain and temperature sensation
1st order: DRG at all levels 2nd: dorsal horn. decussate in ventral white commissure 3rd order: VPL. project to areas 3,1,2 |
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lateral corticospinal tract
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mediates voluntary skilled motor activity, primarily of upper limbs
*not fully myelinated til end of 2nd year (lose Babinski's sign) arises in premotor (6) and primary motor cortex (4) and primary sensory cortex (3,1,2) terminates contralaterally on ventral horn motor neurons *runs in dorsal quadrant of lateral funiculus |
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UMN lesions
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casued by transection of the corticospinal tract
result in spastic paresis with pyramidal signs [Babinski] |
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LMN lesions
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damage to motor neurons
result in flaccid paralysis, areflexia, atrophy, fasciculations, fibrillations ex: poliomyelitis |
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sensory pathway lesion
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ex: tabes dorsalis [dorsal column]
loss of tactile discrimination and position and vibration sense pain and paresthesias also positive romberg sign: (fall over when close eyes w/feet together) |
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Brown-Sequard syndrome
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=spinal cord hemisection
damage to: ->dorsal columns, lateral corticospinal tract, lateral spinothalamic, ventral horn |
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ventral spinal artery occlusion
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causes infarction of anterior 2/3 of spinal cord but spares dorsal columns and horns
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three branches of the trigeminal ganglion
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opthalmic nerve (CN V1)
->wall of cavernous sinus, enters through superior orbital fissure maxillary nerve (CN V2) ->wall of canverous sinus, exits thru foramen rotundum mandibular nerve (CN V3) -> exits thru foramen ovale -> has sensory and motor components |
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ventral trigeminothalamic tract
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pain and temperature sensation from face and oral cavity
3rd order neurons: VPM to brodmann's 3, 1, 2 |
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dorsal trigeminothalamic tract
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tactile discrimination and pressure sensation from face and oral cavity
input from Meissner's and Pacini's corpuscles also project to VPM. |
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trigeminal reflexes
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corneal reflex
jaw jerk reflex tearing reflex oculocardiac reflex [pressure on the globe = bradycardia] |
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Weber's test
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unilateral conduction deafness = hears vibration more on affected side
partial nerve deafness = more on normal side |
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denervation of CN III muscles
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ptosis (no levator palpebrae)
eye looks down and out [unopposed action of lateral rectus and superior oblique] |
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the _____ is the most epileptogenic part of the cerebrum
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hippocampus
sommer's sector is very sensitive to ischemia |
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bilateral destruction/removal of the cingulate gyri
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causes loss of initiative and inhibition
also dulling of the emotions memory is unaffected often used to treat severe anxiety and depression |
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GABA-ergic cells
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purkinje, stellate, basket, golgi cells of the cerebellar cortex
*GLYCINE is the inhibitor NT of the spinal cord. {renshaw cells} |
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glutamate
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major excitatory NT of the brain
neurons project to striatum, subthalamic nucleus, thalamus *can be NEUROTOXIC (esp in huntington's disease) |
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apraxia
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inability to perform motor activites even with intact motor and sensory systems and normal comprehension
lesion usually in Wernicke's area *gait apraxia is a frontal lobe sign seen with normal pressure hydrocephalus |
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problem with local anesthetics in inflammatory tissue
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this tissue is very acidic, so anesthetic will be less effective
lidocaine becomes protonated and gives poor anesthesia |
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superior laryngeal nerve
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internal branch provides sensory innervation to laryngeal mucosa above the vocal folds
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most ischemic damage would be caused by blockage of which cerebral artery?
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middle.. because it is not in the circle of willis (no available collaterals)
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most frequent benign intracranial neoplasm
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meningioma
contains whorls of elongated cells and scattered psammoma bodies is not invasive. main Sx are from mass effect (tends to push down) |
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organization of motor neurons in a spinal cord section
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trunk and proximal muslces are located medially
distal muscles are lateral extensors are anterior flexors are posterior |
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type of hemorrhages that alzheimer patients are prone to
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large lobar hemorrhages often in the parietal lobe
often destroy an entire cerebral hemisphere, resulting in death **due to amyloid deposition in walls of cerebral blood vessels [amyloid angiopathy] |
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hemorrhage of ventral pons
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is a 'locked in syndrome' (pt is aware of being trapped in own body, communicates w/eyelids)
descending corticospinal and corticobulbar fibers are interrupted |
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mechanism of pyridostigmine and neostigmine
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carbamylate the acetylcholinesterase enzyme
[temporarily inhibits the enzyme] |
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internuclear opthalmoplegia
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differs from lesion of oculomotor nerve b/c patient IS ABLE to converge their eyes
(is a lesion of the MLF) |
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occlusion of PICA
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lateral medullary syndrome
->deficits in pain and temperature sensation over contralateral body [spinothalamic] ->ipsilateral dysphagia, hoarseness, diminished gag reflex [vagal, glossopharyng] ->ipsilateral horner's syn ->ipsilateral loss of pain and temp on face [spinal tract and trigeminal nucleus] |
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hemorrhage of internal capsule
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receives blood supply from lenticulostriate arteries (which are prone to damage from uncontrolled HTN)
leads to contralateral dense hemiplegia (paralysis of arm and leg are of same intensity) cranial nerves are also affected (facial in this case) |
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cell types derived from neural crest
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Schwann cells, multipolar ganglion cells, pseudounipolar (spinal and CN ganglia), chromaffin cells of adrenal medulla, odontoblasts, melanocytes, cells that make pia and arachnoid
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structure most affected by subfalcian herniation
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cingulate gyrus (b/c subfalcian crosses the midline) which is just above the corpus callosum
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location of Wernicke's area
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superior temporal gyrus of the language dominant hemisphere
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axons from the olfactory nerve go to _____
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the pyriform cortex [the primary olfactory cortex]
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the insula contains the primary _____ cortex
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taste/gustatory
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nucleus ambiguous
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special visceral efferent fibers of X and IX
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postcentral gyrus
precentral gyrus |
primary sensory cortex
primary motor cortex |
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neurofibrillary tangles
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composed of bundles of paired helical filaments twisted around each other
PHFs result from abnormal phosphorylation of tau [microtubule ass'd protein] |
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how does HIV gain access to the CNS?
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through incoming macrophages
causes subacute inflammation of brain parenchyma ->HIV encephalitis *presence of multinucleated giant cells is very typical |
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chorda tympani
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branch of CN VII
controls salivation from submandibular and sublingual glands parotid is innervated by CN IX |
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stage 2 sleep
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more theta waves than stage 1
sleep spindles and K complexes on EEG |
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REM sleep
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transient large amplitude potentials in occipital areas [PGO spikes = dreaming]
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stage 1 sleep
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= 'drowsiness'
characterized by attenuation of alpha spikes and the initial appearance of theta spikes |
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stage 3 and 4
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high amplitude slow waves, especially delta
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meningiomas
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slow growing benign tumors, most common in the elderly
originate from dura or arachnoid mater often cause osteoblastic rxn in overlying cranial bones **whorls and psammoma bodies** if present as mass lesions, may cause seizures *superior parasagittal surface of frontal lobes is a common site of origin ->produces leg weakness |
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early onset/ Ts21 alzheimer's is due to
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extra copy of APP (amyloid precursor protein) gene
amyloid Beta accumulates within the core of senile plaques |
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drug of choice in pts with status epilepticus
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diazepam [valium]
->a BDZ phenytoin is then administered for long term prevention and seizure control |
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cataracts
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LENS opacifications
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retinopathy of prematurity
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inappropriate proliferation of vessels in inner layer of retina
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retinal damage due to glaucoma
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ganglion cell and optic nerve degeneration
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empty sella syndrome
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pituitary radiologically appears to be absent
sella is filled w/CSF caused by herniation of arachnoid through the diaphragm sella causes pressure atrophy of the pituitary gland also caused by Sheehan's |
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location of visual defect lesions
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central scotomata: macula
ipsilateral blindness: optic n. bitemporal hemianopia: chiasm homonymous hemianopia: tract upper homonymous quadrant: temporal lobe lower " " : parietal lobe macular sparing: occipital lobe |
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pilocytic astrocytoma
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usually affects children
cerebellum, hypothalamus **Rosenthal fibers grade 1 astrocytoma appears as cyst w/a mural nodule** |
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retinoblastoma
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mutation of Rb on chrom 13
neuroepithelial cells that form Flexner-Wintersteiner rosettes if familial: bilateral |
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rare side effect of sumatriptan
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hypertensive crisis
|
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1/2 of cases of intraparenchymal hemorrhages occur here
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basal ganglia and internal capsule
[due to hypertension usually] |
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geniohyoid is innervated by
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C1 [ansa cervicalis]
moves hyoid anteriorly to open the pharynx C1 also innervates thyrohyoid and intra hyoids |
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drooping of the eyelid + mydriasis of the pupil
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lesion of oculomotor nerve
(controls levator palpebrae and parasympathetic fibers of ciliary ganglion) |
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Wernicke-Korsakoff syndrome
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thiamine deficiency, usually secondary to chronic alcohol abuse
confusion, ataxia, vestibular dysfunction, sluggish pupillary light reflexes, oculomotor dysfxn anterograde amnesia and confabulation can occur if untreated |
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Parinaud's syndrome
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pineal tumor that compresses superior colliculi and pretectal area of dorsal midbrain
compression of the superior colliculous causes fixed upward gaze also can cause papilledema by compression of cerebral aqueduct |
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primary CNS lymphoma
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Sx: seizures, headache and CN deficits
often see multicentric lesions, may involve leptomeninges *usually a late manifestation of AIDS medium to high grade B cell lymphoma, typically related to EBV |
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sequence of events for MS demyelinating plaques
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acute: lymphoblastic infiltration and active digestion of myelin
2: hyperplasia of astrocytes transform plaque into gliotic area [axons preserved, but oligodendrocytes diminished] |
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acetazolamide
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carbonic anhydrase inhibitor
leads to reduced production of aqueous humour *for acute treatment of narrow angle glaucoma dorzolamide is for chronic treatment of open-angle glaucoma |
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danger of overdose of TCAs
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fatal arrhythmias
can produce hypotension, shock, death |
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associate acoustic neuromas with____
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neurofibromatosis type II
|
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associate meningiomas with____
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breast cancer, possibly high estrogen states
|
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associate neurofibromas with_____
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neurofibromatosis type I
|
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rate of nerve regeneration when two cut ends have been reconnected
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1 mm/day
|
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internal capsule
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thick band of myelinated fibers that project from cortex to brainstem and spinal cord
OR project from thalamus to cortex lesions cause motor or sensory defects depending on which pathway they affect signs/symptoms = CONTRALATERAL |
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three actions of TCAs
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1: inhibit biogenic amine [NE and 5HT] reuptake at presynaptic neurons
2: induce sedation 3: produce central and peripheral anticholinergic effects |
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Binswanger disease (subcortical leukoencephalopathy)
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neurological symptom ass'd with HTN
diffuse irregular loss of axons and myelin accompanied by widespread gliosis pathology = damage via severe atherosclerosis |
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gag reflex
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CN IX for sensory limb [unilateral]
CN X for motor limb [bilateral] if both are lesioned, then the uvula deviates to the unaffected side when the unaffected side is tapped, and when affected side is tapped, there is no gag at all |
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medulloblastoma
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characterized by BOTH neuronal and glial differentiation
forms grey-white masses in cerebellum of kids, and cerebral hemispheres of adults histo: sheets of densely packed, small poorly diff'd cells |
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CN that lies in the tonsillar fossa
|
glossopharyngeal (IX)
->posterior 1/3 of toungue sensory and taste ->stylopharyngeus muscle (proximal to this point) ->general sensory info to mucosa of the pharynx **gag reflex! [loss of this can lead to death secondary to aspiration pneumonia] |
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drug of choice for myoclonic seizures
|
valproic acid
->is very effective an non-sedating |
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carotid body tumor (paraganglioma)
|
histologically similar to pheochromocytomas
catecholamines are the primary secretions from these tumors |