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49 Cards in this Set
- Front
- Back
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Motor System |
a. Production and use of voluntary mvmt
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Mental Steps to Move |
a. Desire
b. Thought about kind of mvmt u want to make c. Plan d. Execute |
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Primary Cortices (4) |
a. Part of cerebrum dedicated to analysis of single type of neural input
b. First cortical areas to analyze sensory info: - Auditory - Visual - Sensory - Motor |
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Primary Auditory Cortex |
a. Heschl's Gyrus (temporal lobe)
b. Analyze tone patterns c. Localize sound |
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*****
Primary Visual Cortex |
a. Occipital lobe
b. Integrates visual info from both eyes |
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a
Primary Sensory Cortex |
a. Frontal/Parietal lobe (in between the two)
b. Receives neural input about bodily sensation: - pressure - touch - pain - temp |
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aa
Primary Motor Cortex |
a. Precentral Gyrus
b. In the MIDDLE of motor flow c. Receives planned motor impulses from cortical and subcortical areas, but doesn't MAKE plan itself d. Impulses r then sent down thru brainstem and spinal cord and then to musc, themselves |
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aaa
Association Cortex (4) |
a. Areas of cortex that "make sense" of the sensory impulses first analyzed by primary cortex
b. Higher level of processing than in primary cortices: - Temporal association area - Parietal association area - Frontal association area - Occipital association area c. T and P are grouped and called "temporal-parietal association area) |
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aaaa
Parietal Association Area |
a. Integrates bodily sensations w/ visual info
b. Imp role in control of visually guided mvmt (ie: eye-hand coordination) c. Damage may result in difficulty manipulating obj, sensory neglect of half the body, & some reading/wriring deficits |
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aaaaa
Frontal Association Area |
a. Located in the Prefrontal cortex
b. Neural connections w/ lobes of cerebrum c. Receives info on emotion and motivation (Limbic System) so plays imp role in initiating and planning volitional mvmts |
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b
Limbic System |
a. Located in temporal lobe
b. Motivation, drive, and desire to move |
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bb
Basal Ganglia |
a. Collection of nuclei in mid of brain / "nerve knots"
b. Includes: - Caudate Nucleus - Putamen - Globus Pallidus |
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bbb
Lenticular Nucleus |
a. Putamen and Globus Pallidus
b. Structures grouped b/c they're near eachother |
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Striatum |
a. Putamen and Caudate Nucleus
b. Structures grouped b/c they share similar functions |
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bbbbb
Basal Ganglia (Continued) |
a. Anatomically interconnected
b. Imp in planning slow, continuous mvmts |
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c
Damage to BG |
a. Parkinson's - Motor Impairment (not enough)
b. Huntington's Disease - Too much mvmt |
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cc
Connections of BG |
a. Cerebral cortex (info comes in)
b. Striatum (info processed) c. Globus pallidus (info goes out) d. Thalamus e. Cerebral cortex (diff from first) *Also connected with Substantia Nigra to produce Dopamine |
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ccc
BG & Cerebellum |
a. Connections to sensory parts of the brain
b. Constannt flow of mvmt, not back to starting point each time |
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Cerebellum |
a. Regulates musc tone, balance, and fine motor mvmts (writing, speaking coordination)
b. Receives neural impulses of intended mvmt from association cortex c. Rec's sensory input from sensory receptors |
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ccccc
Cerebellum (Continued) |
a. Integrates motor and sensory info - revises plan!
b. Adjusts/refines motor impulses of body's immediate circumstances - sends processed motor signals to thalamus and then to primary motor cortex |
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d
Cerebellum (Continued 2) |
a. Balance
b. Coordinates musc action in stereotyped and non-stereotyped mvmt (writing vs reaching for something) c. Makes sure musc contracts at right time with right force in synchrony w/ other musc to have right production d. Corrects overshooting and undershooting e. For speech, allows smooth flow from one artic position to next |
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dd
Mental Steps to Move & Brain Parts |
a. Desire = Prefrontal Cortex
b. Info refined/processed = Cerebellum & Basal Ganglia c. Info sent to/further refined by Thalamus ( Primary Sensory Relay Station of Brain, except taste and smell) d. Info sent to Primary Motor Cortex |
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ddd
Cerebellum Lesion Effects |
a. Broad, discoordinated gait
b. Hypotonia (low musc tone) c. Decomposition of mvmt into component parts - jerky d. Ataxia (Errors in speed/force/range of mvmt) e. Dysmetria (Overshooting and undershooting) f. Intention Tremor (Tremors only when moving - maybe compensatory for Dysmetria) |
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dddd
Thalamus |
a. Grey matter
b. Relay station for sensor and motor info c. Rec's neural inputs of planned motor mvms from BG and cerebllum d. Uses sensory info to refine motor impulses from BG and cerebellum e. Sends resulting info to diff parts of CNS |
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ddddd
Limbic System |
a. Generates emotional and drive related responses
b. May provide /intentional aspect to communication c. Lesion = mutism |
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e
Primary Motor Cortex 2 |
a. Rec's neural motor impulses that have been processed, smoothed, and coordinated by: BG, Cerebellum & Thalamus
b. Neurons here have longest axons in body: they extend from cortex to lower portions of spinal cord c. These axons = desc motor tract = Pyramidal System |
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ee
Role of Primary Motor Cortex (3) |
a. Take voluntary mvmt patters that are formulated elsewhere
b. Transmits them to cranial or spinal nerves via pyramidal system c. Integrates info from other cortical areas into planned mvmt (premotor and supplementary motor area provide additional input just before mvmt is initiated) |
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eee
Premotor & Supplementary Motor Areas |
a. Neural impulses from the PMA and SMA exert further control over final motor signals sent out by primary motor cortex
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Premotor Motor Area |
a. Impulses from here are imp in visually-guided mvmts (put key in lock, thread needle)
b. If damaged, hand mvmt is clumsy |
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Supplementary Motor Area |
a. Imp in planning and learning complex, internally generated mvmts - even if just thinking about moving something
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f
Descending Motor Tracts |
a. The neural pathways that travel from cortex to brainstem & spinal cord
b. Connections w/i CNS c. Two types: Pyramidal and Extrapyramidal Systems (compliment each other) |
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ff
Pyramidal System |
a. Carries impulses that control voluntary, fine motor mvmt like speech
b. Works at conscious level |
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fff
Pyramidal System (Continued) |
a. Nerve fibers take direct path from primary motor cortex to brainstem or spinal corrd where they synapse with cranial or spinal nerves
b. Direct rte c. 2 divisions of fibers: Corticobulbar and Corticospinal Tracts |
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Corticospinal Tract |
a. Axons desc from cortex to
b. Internal capsule to c. Brainstem to d. Motor neurons of spinal cord * Many of these axons synapse w/ spinal nerves |
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fffff
Corticospinal Tract (Continued) |
a. Axons of Upper Motor Neuron (cortical neuron) then pass down to Medulla
b. Most fibers cross midline in medulla = pyramidal decussation and then continue to opp side of spinal cord c. Axons then synapse with 2nd neuron = Lower Motor Neurons which then run to musc |
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g
Corticobulbar Tract |
a. Axons desc from cortex and
b. Terminate in brainstem then c. Synapse on cranial nerves d. Starts lower than CS Tract NB: bulbar = old name for medulla |
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gg
Corticobulbar Tract (Continued) |
a. Do NOT cross at midline (usually)
b. Beginning in Midbrain, these fibers sep from CS fibers into bilateral pattern before synapsing with Cranial Nerves c. Bilateral pattern results in bilateral cortical innervation for most cranial nerves, so stroke effecting fibers in one hemi will still receive motor innervation from undamaged hemi d. Musc in upper face, jaw, larynx, and velum receive bilateral info, unlike lower face and tongue with are contralateral only |
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ggg
Damage to Pyramidal System |
a. Musc weakness ad rapid fatigue
b. Unilateral damage to pyramidal system can result in loss of fine motor mvmt of articulators = Unilateral Upper Motor Neuron Dysarthria (UUMN) c. Usually affects neighboring tracts, as well |
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gggg
Extrapyramidal System |
a. Transmits impulses that control musc tone (postural support) needed by fine motor mvmts
b. Unconscious and automatic c. Commuter train w/ multiple stops to peripheral nerves that originates in Brainstem (and stimes Cortex) |
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ggggg
Two Systems Compared |
a. Operates in parallel w/ pyramidal system
b. Less info known about effects EPS has on cranial nerves and musc of speech production - might influence reflexes, musc tone, and some voluntary mvmts of speech mech |
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h
Upper Motor Neurons |
a. Contained w/i CNS
b. Motor neurons in cortex plus desc corticospinal and corticobulbar tracts c. Also include pathways of EPS |
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Lower Motor Neurons |
a. Motor neurons in brainstem or spinal cord, plus peripheral nerve
b. Innervated by UMNs c. Axons pass thru ventral root d. They innervate collective of musc fibers - the motor unit e. Everything from the 2nd neuron down |
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hhh
Lesions of UMNs (3) |
a. Spastic paralysis
b. Hypertonia (increased musc tone) c. Exaggerated reflexes |
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Lesions of LMNs (3) |
a. Flaccid paralysis
b. Fasciculations (brief contraction of musc) c. Atrophy (lose musc bulk) |
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hhhhh
Cranial Nerve Nuclei |
a. Cranial nerves are attached to brainstem at points of cranial nerve nuclei
b. S & M fibers branch our sep from brainstem c. Cell bodies of sensory neurons gather in cranial ganglion d. Cell bodies of LMN r grouped inside brainstem e. LMNs in cranial nerves synapse w/ UMNs from PS and EPS w/i brainstem |
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i
Cranial Nerves (12) |
I. Olfactory - S (smell)
II. Optic - S (ability to see) III. Oculomotor - M (eye mvmts) IV. Trochlear - M (eye mvmts) V. Trigeminal - S&M (facial sensation) VI. Abducens - M (eye mvmts) VII. Facial - S&M (facial expression, taste) VIII. Vestibulocochlear - S (balance, hearing) IX. Glossopharyngeal - S (taste and swallowing) X. Vagus - S&M (taste and swallowing) XI. Accessory - M (neck and shoulders) XII. Hypoglossal - M (tongue mvmt) NB: Sensory fibers = afferent |
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ii
Neuromuscular Junction |
a. Where axon terminal ends on musc fibers
b. Motor neuron makes functional contact w/ musc tissue c. Spinal nerves = bundle of fibers w/ axons |
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iii
Neuromuscular Junction (Continued) |
a. When neural impulse traveling dwn axon reaches terminal branch, acetylcholine is released into gap b/w axon and musc cell
b. When enuf ACH is released, musc fiber will contract |
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iiii
Damage to Motor Speech System |
a. Will result in movement disorder
b.Can result in motor speech disorder c. Site of lesion will determine what particular motor speech disorder the person presents with |
