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63 Cards in this Set
- Front
- Back
3 divisions of somatosensory of the Trigeminal Pathway
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-fine touch and vibration
-pain and temperature -proprioception |
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3 Sensory branches of the trigeminal nerve (CN V)
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opthalmic (V1)
maxillary (V2) mandibular (V3) |
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Location of soma of the Orofacial fine touch and vibration pathway
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1. soma in trigeminal ganglion
2. soma in chief sensory nucleus 3. soma in posterior medial thalamic nucleus (VPM) |
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Location of soma of the Orofacial pain and temperature pathway
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1. soma in trigeminal ganglion
2. soma in spinal trigeminal nucleus 3. soma in posterior medial thalamic nucleus (VPM) |
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Location of soma of the Orofacial proptioceptive pathway
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1. soma in mesencephalic nucleus (brainstem)
2. trigeminal motor nucleus -> sends axons out V3 (m. of mastication) *Does not have soma in trigeminal ganglion |
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organization of motor cell bodies in the ventral horn of the spinal cord
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flexor -> more lateral
extensor -> more medial distal muscles -> more ventral proximal muscles -> more dorsal/medial |
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Name the 4 descending motor pathways
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1. corticobulbospinal tract
2. rubrospinal tract 3. reticulospinal tract 4. vestibulospinal tract |
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Corticobulbal synapses
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red nucleus, cranial nerves III, IV, V, VI, VII, X, XI, XII and reticular formation
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Location of corticospinal fibers in the internal capsule
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posterior limb of the internal capsule
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Location of the corticobulbar fibers in the internal capsule
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genu of the internal capsule
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At the level of the midbrain what forms the crus cerebri (cerebral peduncles)
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corticospinal fibers
(corticobulbar fibers are located just medial) |
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What happens to the fibers of the corticobulbospinal system in the Pons and in the Medulla
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fibers scatter in the pons and condense in the medulla to form the meduallary pyramids
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Function of Lateral Corticospinal Tract
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movement of extermities
(most clinically important descending motor pathway) |
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Function of the Anterior Corticospinal Tract
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movement of axial muscles
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Injury or disease to Lower Motor Neuron
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1. paralysis of m. innervated by these fibers
2. loss of m. tone (hypotonia) 3. atrophy of denervated m. 4. absent myotatic (deep tendon) reflexes |
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Upper motor neuron lesion
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1. paresis or paralysis of m. involved
2. increased m. tone (hypertonia, rigidity, spasticity) 3. hyperactive myotatic (deep tendon) reflex 4. Babinski sign 5. m. atrophy not seen initially but due to long tern disuse |
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Function of the Basal Ganglia
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'consultant' to the cerebral cortex
(link between the idea of a movement and the motor expression of that idea) |
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Lesion to the basal ganglia
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disturbance in the initiation and cessation of a motor event
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3 nuclei of the basal ganglia
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- caudate nucleus
- putamen - globus pallidus |
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collective name for the nuclei of the basal ganglia
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corpus striatum
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neostratium
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caudate nucleus and putamen
(basal ganglia nuclei) |
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lentiform nucleus
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putamen and globus pallidus
(basal ganglia nuclei) |
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paleostriatum
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globus pallidus
(basal ganglia nuclei) |
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What 2 basal ganglia nuclei does the anterior limb of the internal capsule separate?
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head of the caudate from the putamen
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2 nuclei that are closely associated with the basal ganglia
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-substantia nigra
-subthalamic nucleus |
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corticostriatal fibers
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all areas of the cortex to the basal ganglia
[glutamate as excitatory NT -> will increase the firing of post-synaptic neurons] |
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Substantia nigra
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midbrain structure that provides input into the basal ganglia
[provide a high concentration of dopamine in the basal ganglia, and is tonically active] |
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direct pathway within the basal ganglia _______ a flow of information through the thalamus
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facilitates
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indirect pathway within the basal ganglia _______ information flow though the thalamus
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inhibits
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How is Parkinson's Disease involved with the basal ganglia
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PD has a loss of dopaminergic neurons of the substantia nigra (SN)
-activates the indirect pathway -removes source of activation of the direct pathway |
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Ballismus
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violent, flinging movement occurring in proximal musculature
-due to damage to the subthalamic nucleus -> increased motor output |
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Huntington's Chorea
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loass of cells in striatum that give rise to the indirect pathway of the basal ganglia ->increased motor output from cerebral cortex with accompanying hyperkinetic disturbance
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limbic loop
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nucleus accumbens (limbic system dealing with pleasure and emotion) to the basal ganglia
-> giving motor expression to emotion |
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enkephalins
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endogenous opioids
-inhibitory neurotransmitters (mostly found in small interneurons) |
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How do endogenous opioids produce post synaptic and pre-synaptic inhibition?
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Post synaptic inhibition - opens K+ channels
Presynaptic inhibition - closes Ca2+ channels on presynaptic nerve |
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naloxone
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opioid antagonist
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Functions of the cerebellum
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reduce error in movement through its connections with upper motor neurons
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When does the cerebellum act?
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during and before motion
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cerebellum functions to maintain posture, _____ _____, and equilibrium
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muscle tone
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Where do cerebellar efferents reach?
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brain stem, spinal cord, and cortex
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4 cerebellar nuclei embedded in the white matter (deep)
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lateral to medial
- dentate nucleus - emboliform nucleus - globose nucleus - fastigial nucleus (don't eat greasy foods) |
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3 lobes of the cerebellum
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anterior, posterior,flocculonodular
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folia of the cerebellum
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folds
I through X (rostral to caudal) |
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What are the three connections between the cerebellum and the rest of the CNS
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Superior cerebellar peduncle
Middle cerebellar peduncle Inferior cerebellar peduncle |
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Interposed Nuclei of the cerebellum
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emboliforn nucleus and globose nucleus
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3 layers of the cerebellar cortex from superficial to deep
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molecular layer -> Purkinje layer -> Granule layer
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5 cell types found in the cerebellar cortex
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Molecular layer [Stellate cell (GABA) & Basket cell (GABA)]
Purkinje layer [Purkinje cell (GABA)] Granule layer [Golgi cell (GABA) & Granule cell (glutamate)] |
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excitatory axons that project into the cerebellum
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mossy fibers and climbing fibers
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What 3 pathways involve the cerebellum?
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-vestibulocerebellar pathway
-spinocerebellar pathway -cerebrocerebellar pathway |
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vestibulocerebellar pathway
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pathway that takes into account head movement and allows the cerebellum to influence eye, neck, and leg movement
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3 spinocerebellar inputs to the cerebellum
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-dorsal spinocerebellar tract (DSCT)
-ventral spinocerebellar tract (VSCT) -cuneocerebellar tract |
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types of movements produced by cerebellar pathology
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ataxic movement - jerky and inaccurate movement
dymetria - overshooting and undershooting movements dysdiadochokinesia - inability to perform rapid alternating movements |
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functions of the vestibular system
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-coordinate position and acceleration of head
-coordinate eye movement and head movement to keep retinal visual image stationary -reflex postural adjustments (maintain balance and posture) |
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Vestibular sensory apparatus
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bony labyrinth (interconnected cavities in the temporal bone) suspends the membranous labyrinth (water ballon)
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4 regions within the membranous labyrinth
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cochlea, saccule, utricle, semicircular canals
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utricle
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large bulbous structure at the base of the semicircular canals
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saccule
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bulbous structure that lies between the utricle and cochlea
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Macula
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sensory structure within the utricle and saccule that is sensitive to linear head acceleration
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Crista
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sensory strucuture within the semicircular canals that is sensitive to rotational acceleration of the head
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4 vestibular nuclei
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superior, inferior, medial, lateral vestibular nuclei
(contain 2nd neuron in pathway) |
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function of the medial vestibulospinal tract
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uses info from the vestibular system to initiate movement of the cervical flexors and extensors
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function of the lateral vestibulospinal tract
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uses info from the vestibular system to initiate movement of axial and proximal limb muscles
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function of the vestibulo-thalamocortical pathway
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know if balanced or not
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