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38 Cards in this Set
- Front
- Back
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INNERVATION OF THE TONGUE
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GENERAL SENSORY:
- CN 5: anterior 2/3 - CN 9: posterior 1/3 TASTE: Fungiform papillae: anterior 2/3, Foliate papillae: posterior of tongue - CN 7: Fungiform & anterior foliate & palate Circumvallate Papillae: post 1/3 tongue. contains 1/2 of all taste buds. - CN 9: Circumvallate & most foliate papillae & pharynx - CN 10: taste buds of epiglottis & esophagus |
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TASTE PATHWAYS:
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1. CN 7: Chorda tympani & greater petrosal --> geniculate ganglion
CN 9: Petrosal ganglion CN 10: nodose ganglion 2. all terminate in rostral part of solitary nucleus 3. UNCROSSED fibers in CTT 4. VPM of thalamus 5. Gustatory cortex: insula & medial part of frontal operculum (6. fibers project from gustatory cortex to orbital cortex of frontal lobe - join olfactory info & to amygdala --> limbic system). |
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TASTE RECEPTORS
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1. SALT: ^ Na+ levels depolarize
2. ACIDS: H+ depolarize by moving through Na+ channels or blocking pH sensitive apical K+ channels 3.SWEET: G protein-coupled R & 2nd msger (cGMP?) = decreased K+ conductance 4. BITTER: ligand-gated, G-protein coupled, or ligand-gated K+ channels = decreased chance of opening or cause Ca+ release |
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SMELL PATHWAY:
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CN 5: Respond to noxious odors/irritants
CN 1: UNMYELINATED Bipolar cells - bulbous termination = olfactory vesicle with cilia embedded in mucus - olfactory filia penetrate cribiform plate & terminates in olfactory bulb - Mitral Cell: make up axons of olfactory tract - ends up in the UNCUS (fibers cross via anterior commissure) |
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cells of smell
**olfactory receptors are constantly replaced throughout lifetime** |
- Olfactory receptors: ALL use receptor proteins coupled to G proteins
--> opens cation channel: ^ Na+ & Ca2+ --> axons end in glomeruli - mitral cells: synpase with glomeruli - Granule & tufted cells: interneurons. insulate glomeruli - CENTRIFUGAL fibers: axons from other areas of CNS. allows for fine-tuning of smell. |
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SENSORY RECEPTORS & ACUPUNCTURE
- type II/AB - type III/Ad - Type IV/C |
TYPE II/Ab: NUMBNESS
TYPE III/Ad: fast pain; SHARP INITIAL PAIN TYPE IV/C: slow pain - stronger intensity, slow, dull, longer lasting secondary pain |
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PAIN STIMULUS
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CHANNEL 1 --> LAMINA II --> (STT/SMT) --> RT --> THALAMUS --> higher brain
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ACUPUNCTURE STIMULUS
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1. Channel 2 --> lamina I/II
A. PRESYNAPTIC INHIB: local release of dynorphins & enkephalins 2. SMT/SRT/STT --> THALAMUS, BS, HYPOTHALAMUS B. POST-SYNAPTIC INHIB: collaterals from brainstem 2 PAG & LC activate inhibitory interneurons in SC --> release serotonin, dopa, & NE C. collaterals to arcuate nuc & hypothalamus --> BETA-ENDORPHINS & pituitary gland act. 3. Thalamus --> higher brain |
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ACUPUNCTURE'S EFFECT ON BRAIN STRUCTURES
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PRIMARY SOMATOSENSORY CORTEX: ACTIVATED (but not as much as tactile stimulation
DEEP STRUCTURES (limbic): DECREASED/INHIBITION - also decreased cerebellar activity **de qi has different effects on CNS than regular tactile stimulation & pain!!** - modulates the pain neuro-matrix & the default network (more activated at rest) |
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ACUPUNCTURE IS PARAMETER-DEPT
- low freq - high freq |
LOW FREQ EA: deactivates bilateral hippocampus
- moderate, prolonged anithyperalgesic & anti-inflamm effect **use for chronic pain** HIGH FREZ EA: deactivates contralateral amygdala (fear) - potent, short-term inhibitory effct on hyperalgesia (little effect on inflamm) |
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ANALGESIC MECHANISM OF ACUPUNCTURE
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1. SC: laminae I & II: enkephalins & dynorphin
2. SUPRASPINAL: bs, hypothalamus, and thalamus 3. NTs: dopa NE serotonin 4. Endogenous opioid pain control system: periaqueductal gray & RVM 5. Perception/Processing of pain: modulate limbic system & default network |
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ACUPUNCTURE & NEURO-ENDOCRINE-IMMUNE MODULATION
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ANTI-INFLAMMATORY
1. EA --> ^ ACTH 2. ^ Vagal activity: cholinergic anti-inflamm pathway (decreased symapthetic activity & ^ immune fxn) 3. ^ corticosterone (and decreased limb edema) |
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ACUPUNCTURE & CARDIOVASCULAR REGULATION
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USE MA & LOW FREQ EA
- affects sympathovagal balance - vlPAG = cardiovascular depressor region - mu & delta-opiods: beta endorphins, endomorphin, & enkephalins (NOT dynorphins - 100hz) **DOESN'T REDUCE BP IN NORMAL PTS** - acupuncture shifts things back to normal |
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HAIR CELL
- depolarize - high/low freq - electrical/mechanical tuning - axis of sensitivity |
INFLUX of K+ depolarizes hair cell (high endolymph [K+])
- Inward Ca2+ depolarizes --> Outward Ca2+/K+ current BASE: high freq APEX (Helicotrema): low freq Mechanical tuning: position on basilar membrane Electrical tuning: sontaneous electrical oscillations axis of sensitivity is in direction of basal body |
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AUDITORY NUCLEI
**auditory info goes from SON to CN 7 nucleus --> dampen sound via stapedius** **lateral lemniscus: info from SON to Inf. Colliculi** |
CHOCHLEAR: dorsal & lateral --> ICP
SUPERIOR OLIVARY NUCLEI (son): detect time differences in sound arriving to the 2 ears (UNCONSCIOUS) ACOUSTIC STRIA: cross the midline - dorsal, int., trapezoid body spiral gang -> cochlear nuclei --> SON (bilateral) --> Inferior colliculus (conscious) --> medial geniculate body --> auditory cortex (heschl's gyrus) = localization of sound |
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CN 5 & 7 IN HEARING
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CN 5: TENSOR TYMPANI - dampens sound
CN 7: STAPEDIUS |
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High vs. Low frequency
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high freq: uses intensity differences
low freq: uses time differences (detected by SON) - closer to apex/helicotrema |
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ACOUSTIC SCHWANNOMA/NEUROMA
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~50 YO
- unilateral mostly - tinnitus - vertigo - **positional vertigo test ** always check orthostatic HR, BP |
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VESTIBULAR SYSTEM
- semicircular canals - saccule - utricle |
SEMICIRC: ANGULAR ACCELERATION 9endolymph)
SACULE: vertical acc UTRICLE: linear acc. **maculae are curved sheets of cells --> respond to both horizontal & vertical movement** |
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VESTIBULAR GANGLIA & NERVE
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SUPERIOR GANG: ant & lateral canals
INFERIOR GANG: Post canal, utricle, saccule axons --> vestibular n. --> cerebellopontine angle. |
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TASTE BUD INNERVATIONS
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cn 7, 9, 10
(cn 5 = general sensation of tongue) |
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CT
- least/most dense - examples |
black (least dense) --> white (most dense)
air > water/csf > soft tissue > blood >> Ca2+ (bone) |
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CONTRAST ENHANCEMENT IN CT/MRI
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NORMAL BRAINS WILL BE UNCHANGED BY ADDITION OF CONTRAST
- contrast agents DON'T cross BBB - they INCREASE SENSITIVITY of the test |
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ADVANTAGES/DISADVANTAGES OF CT
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GOOD:
- FAST - ACUTE HEMORRHAGE - BONE IMAGING BAD: - CAN'T IMAGE BRAIN STEM/CEREBELLUM (post. fossa) - can't get sagittal images - less sensitive overall (strokes might not show up for many hours) **USE IF YOU SUSPECT HEMORRHAGE OR FRACTURE** |
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ADVANTAGE/DISADVANTAGES OF MRI
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GOOD:
- PREFERRED METHOD B/C MORE SENSITIVE - BETTER 2 SEE POST. FOSSA BAD: - SLOW - SIGNIFICANT MOTION ARTIFACT - CONTRAINDICATIONS: pacemaker & aneurysm clips **poor sensitivity 4 bone lesions** |
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EPIDURAL HEMATOMA
(case 1) |
- young person
- trauma - SLEEPY (INCREASED intracranial P) signs: - brief unconsciousness @ trauma - post. L hemisphere lesions: right side motor loss, wernicke's aphasia, can't follow commands DO A FREAKING CT SCAN - trauma/hemorrhage risk = bright wedge-like hematoma (acute blood) MEDICAL EMERGENCY DAMNIT |
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STROKE
(CASE 2) |
- OLD PERSON
- SUDDEN ONSET = vascular - "denial" - "i have a virus; it's nothing" signs: - Left side motor wkness - Left homonoymous hemianopsia - increased reflexes on left side - pt DENIES weakness - HEMINEGLECT --> RIGHT PARIETAL LOBE **MCA STROKE = LATERAL HEMISPHERE** (affects optic radiations precentral gyrus) = STENOSIS IN RIGHT MCA |
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EPIDURAL VS SUBDURAL HEMATOMA
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EPIDURAL: arterial (middle meningeal)
- young - trauma (acute); asscd with skull fracture - CT scan; bright white blood SUBDURAL: venous (sinuses) - old - chronic bleeding - hematoma "layers out" over brain. |
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DISC HERNIATION (WITH RADICULOPATHY)
CASE 5 |
- 55 yo
- PROGRESSIVE gain instability - motor weakness in R shoulder area - ABSENT biceps reflex & BRISK triceps reflex - BRISK LEG REFLEXES W/ CLONUS - BILATERAL BABINSKI - DECREASED SENSATION IN BOTH LEGS lesion is @ C5/6 - UMN & radiculopathy DO A FREAKING MRI - surgery.... |
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ACOUSTIC SCHWANNOMA
(CASE 6) - mass lesion (slow progression) - pushes on cerebellum |
-PROGRESSIVE HEARING LOSS in left ear
- + tinnitus & vertigo/dizziness (spinning) - Progressive left side "clumsiness" - DROOPY left facE (CN 7) - NYSTAGMUS when looking left - ATAXIS with finger/nose & heel/shin = LESION @ CEREBELLOPONTINE ANGLE - CORNEAL REFLEX TESTING: Left eye doesn't close as fast (cn 7 & 5) DO A FREAKING MRI!!! |
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GLIOBLASTOMA (MALIGNANT BRAIN TUMOR)
CASE 7 |
- PROGRESSIVE left side weakness
- RHYTHMIC shaking of left side + generalized tonic-clonic seizure (eyes looking to the left) (right brain drives eyes to right) - SLEEPY (not high brain P) - motor weakness & hyperreflexive RIGHT HEMISPHERE GLIOBLASTOMA - ring-enhancing region |
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ALZHEIMER'S
(CASE 8) |
PROGRESSIVE MEMORY LOSS (4 yrs)
- dementia = CORTICAL LESION - ATROPHY OF BRAIN (not true hydrocephalus) **true hydrocephalus does NOT have atrophy in the periphery** |
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PCA STROKE
(CASE 9) |
- Hx of a-fib (major stroke RF)
- LEFT EYE SUDDEN LOSS - runs into garbage can on left side = LEFT HOMONYMOUS HEMIANOPSIA WITH MACULAR SPARING!!! = R PCA STROKE (macular sparing); cardioembolic |
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SUBARACHNOID HEMORRHAGE
(ruptured aneurysm) CASE 3 CT --> angiogram nec to clip aneurysm |
SUDDEN ONSET HEADACHE (WORST EVER) = vasc
- SLEEPY (increased brain P) --> coma - PAIN W/ NECK FLEXION (meningeal irritation) DO IT A CT CUZ IT'S AN EMERGENCY --> do a LP & check for blood if CT seems ok CT SCAN: bright blood all around quadrigeminal plate (around midbrain), extending into ventricular system |
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HUNTINGTON'S DISEASE IMAGING
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- movement disorder
- dementia - family hx * EARLY ATROPHY OF CAUDATE NUCLEUS * - don't see it bulging into lateral ventricle = GENERALIZED ATROPHY OF THE BRAIN |
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MULTIPLE SCLEROSIS
- multiple focal demyelination CASE 4 |
- YOUNG WOMAN
- double vision looking left - right eye cloudiness - legs weak/numb - Right eye doesn't move past midline (MLF) when looking Left - hyperreflexia of LEFTs & bilateral babinski Unexplainable with SINGLE lesion: MLF, optic neuritis., and SC all affected DO AN MRI!! **white spots: demyelination usually around lateral ventricles |
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flocculo-nodular lobe of cerebellum
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vesitbulo-cerebellum
- striaght there via ICP = mossy fibers |
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MLF
- ASCENDING - DESCENDING |
ASCENDING:
- TO CN 3,4,6 - conjugate eye movements - PPRF DESCENDING: 1. MEDIAL vestibulospinal projections: control head & neck mm - INHIBIT alpha & gamma motor neurons - INHIBIT FLEXOR muscle tone - "core" mm. 2. LATERAL vestibulospinal tract: - EXTENSOR pathway - posture; antigravity mm. 3. RUBROSPINAL TRACT: flexors of spinal reflexes & tone |
