Neuroanatomy and Neurophysiology. Sensory Motor Afferent Vision Kinesthesia Olfaction Hearing Taste Pain Temperature Touch Balance Efferent Glands Muscle

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  • Neuroanatomy and Neurophysiology
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  • Sensory Motor Afferent Vision Kinesthesia Olfaction Hearing Taste Pain Temperature Touch Balance Efferent Glands Muscle Organs Circulation Digestion Respiration Excretion Reproduction
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  • , Viscera
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  • Dendrite Cell Body Axon
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  • Boutons contain: - neurotransmitters for excitation or inhibition of response -mitochondria for energy generation and protein development
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  • Presynaptic neurons Postsynaptic neurons
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  • Meningeal Lining protective and nutritive function
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  • Cortex=Bark 6 layers of cells Pyramidal motor cells Non Pyramidal sensory cells
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  • Broadmans Map 1,2,3,4,6,8,17,18,22, 41,42,44,45
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  • Fissure Gyri Sulci Frontal Lobe precentral gyrus supplemental motor area inf. frontal gyrus= pars operculum= Brocas Area Parietal Lobe postcentral gyrus supramarginal gyrus angular gyrus Temporal Lobe superior temporal gyrus Heschls Gyrus Wernickes Area Occipital Lobe calcarine sulcus
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  • Corona Radiata Myelinated Fibers Projection to and from cortex to brain stem, spinal cord Corona Radiata Association links regions of same hemisphere Short connect one gyrus to the next Long interconnect lobes of the brain of the same hemisphere- arcuate fasciculus Commissural from one location on one hemisphere to the corresponding location in the other corpus callosum
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  • Subcortical Structures Basal Ganglia Control of background movement initiation of movement patterns Lesions basal ganglia = extrapyramydal dysfunction including hypokenetic and hyperkenetic dysarthria
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  • Cerebrovascular System Carotid Division ext&int carotid Int. carotid = Ant. Cerebral a. Mid. Cerebral a. Vertebral Division ant&post spinal a. basilar arteries = sup/ant cerebellar a. post cerebral a.
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  • Cerebralvascular Obstruction Thrombosis is a stationary obstruction Embolus is a traveling clot that obstructs Aneurysm is a dilation or ballooning of a vessel wall which can cause a rupture into surrounding space Congenital, AVM Trauma CVA, TIA
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  • Anatomy of the Brainstem
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  • II
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  • Olfactory I Reaches the brain without going through thalamus Olfactory cortex in pyriform lobe and hippocampal formation
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  • CN II Optic Nerve
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  • CN III oculomotor CN IV Trochlear CN VI Abducens
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  • CN V Trigeminal Sensory/motor 3 branches opthalmic: transmits sensory information from skin of the upper face maxillary: transmits sensory information from the middle face mandibular: sen/mot sensory from lower face, kinesthetic/proprioceptive sense of m. of mastication, sen. ant. 2/3 of tongue & floor of mouth (pain/temp), motor innervates m. of mastication, tensor tympani and veli palatini, mylohyoid, ant. belly of digastric
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  • UMN Damage: increased jaw jerk reflex LMN Damage: atrophy/weakne ss of affected side, jaw pulls to unaffected side on closure bilateral-jaw hangs open TVP damage: hypernasality
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  • Upper face innervated bilaterally Lower face contralateral Efferent for facial m. Afferent: -taste ant. 2/3 tongue -sublingual/submandibular glands UMN damage: no upper face paralysis LMN damage: upper/lower face paralysis on side of lesion VII CN S/M Facial
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  • VIII CN S/M Vestibulocochlear
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  • IX CN S/M Glossopharyngeal Part of Pharyngeal Plexus Efferent stylopharyngeus Afferent taste posterior 1/3 tongue, soft palate Pain, temp., touch posterior 1/3
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  • X CN Vagus S/M Pharyngeal, superior, and laryngeal branches important in voice, speech, and swallowing Lesions can cause: Lack of sensation in pharynx Lack of muscle function: palate, pharynx, vocal fold, esophagus Large autonomic role
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  • IX CN Accessory M Part of pharyngeal plexus for innervation of larynx, pharynx, and soft palate Sole innervation for trapezius and SCM
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  • XII CN Hypoglossal M Innervation for the motor function of the tongue Each hypoglossal nucleus served by contralateral corticobulbar tract (L) UMN damage = (R) tongue weakness (L) LMN damage = (L) tongue weakness Fibers of the Corticobulbar Tract decussate prior to reaching the hypoglossal nucleus, therefore (L) UMN damage/ (R) LMN damage = (R) tongue weakness
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  • Dorsal Root + Ventral Root = Spinal Nerve = Dorsal & Ventral Rami Branches of ventral rami go to sympathetic ganglia, nuclei of ANS Efferent neurons of dorsal and ventral rami go to motor end plates/muscle synapse Spinal Reflex Arc
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  • UMN: commands from upper brain levels that activate or inhibit muscle function by synapsing with LMN LMN: dendrites and soma within the spinal cord,axons/components that communicate with muscle fiber Neuron within ventral gray matter is LMN or Final Common Pathway
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  • UMN/LMN LMN Damage: muscle weakness or complete paralysis, reflexes not intact UMN Damage: muscle weakness or complete paralysis, reflexes intact because a spinal arc reflex is a LMN process
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  • AST Tract: transmits info. On sense of light touch from spine to thalamus Ipsilateral: sensations on the same side as they enter the cord Contralateral: sensations on the opposite side as they enter the cord Decussate: cross the midline
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  • Corticospinal Tract Pyramidal Tract Voluntary Movement Modification of Reflexes Visceral Activation Two neuron pathway consisting of an UMN and LMN
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  • Corticobulbar Tract Arises from: cortical cells in lateral aspects of pre central gyrus premotor/somesthetic regions of parietal lobe Axons will: branch/decussate at different levels of brainstem synapse with nuclei of CN Sensory Information: facilitate/inhibit transmission to thalamus Serves: CN for speech
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  • Higher Functioning Primary activity areas: receive information from senses, extract info. Adjacent higher order areas of processing (secondary, tertiary,quaterary): info. compared to other info. received and stored associated with modality Association areas: highest level of cognitive processing
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  • Motor Function Identify target: tongue tip to alveolar ridge Spacial orientation: integration of information of body parts in space Posterior parietal lobe receives information from thalamus, cerebellum, basal ganglia Develop plan to achieve target behavior Premotor region, area 6, anterior to motor strip plans the action, receives info from areas 1,2,3 re location of muscles and joints SMA, area 6 sup. & med., preparatory speech act, initiation of speech act Execute plan: muscle movement with accurate timing force and rate Area 4 execution of voluntary movement
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  • Motor System Lesions Dysarthria: speech disorder arising from paralysis, muscular weakness, and dyscoordination of speech musculature Flaccid Dysarthria: LMN damage of CN, dysphonia due to VF paralysis, fasciculations, hypotonia, reflexive responses reduced or absent Spastic Dysarthria: UMN bilateral damage to pyramidal or extrapyramidal tracts, hyper- reflexia, hypertonia UUMN: less devastating than bilateral
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  • Motor System Lesions Ataxic Dysarthria: Damage to the cerebellum &/or brainstem vestibular nuclei Loss of coordination, unable to achieve articulatory target, problems in coordination of rate, range, and movement Dysdiadochokinesia Dysprosody
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  • Motor System Lesions Hypokenetic Dysarthria: paucity of movement, inhibited initiation of movement, reduced ROM, rigidity, pill rolling hand tremor Damage to BG &/or substantia nigra (SN) SN produces Dopamine (DA) which balances acetylcholine (Ach), decreased DA results in inhibited initiation of motor function Speech rushed, reduced duration of speech sounds, monopitch, monoloudness
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  • Motor System Lesions Hyperkenetic Dysarthria:Extraneous involuntary movement caused by BG circuit damage Subthalamic N. damage: inhibition to GP is lost resulting in Ballism (uncontrolled flailing) BG damage: if Ach is decreased and DA increased choreiform, involuntary twitching and movements, result Tics: rapid movements of small groups of muscle fibers Tremors: rhythmic contractions Athetosis: slow, writhing movements Dystonia: involuntary movement to a posture, posture held briefly
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  • Motor System Lesions Mixed Dysarthria: Damage to more than one of the controlling systems S/F: found in ALS, disease of UMN & LMN S/A: found in MS, UMN and cerebellum S/A/hypo: Wilsons disease (hepatolenticular degeneration)
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  • Motor System Lesions Apraxia/Dyspraxia: A dysfunction of motor planning in the absence of muscular weakness or dysfunction SMA damage: difficulty