pathways2 - 1. Head movement causes fluid in the three...

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Somatosensory: Dorsal  Somaosensory: ventral Vestibular Pathway 1. Sensation enters the periphery via  sensory axons. 2. Sensory neurons have their cell  bodies outside the spinal cord in a  clump called dorsal root ganglia. 3. Neurons go up spinal cord  immediately. 4. At medulla, secondary afferents  cross and form a new tract on the  other side of the brainstem. 5. Thalamus. 6. VPL 7. Primary somatosensory cerebral  cortex. *Corpuscles sense deep pressure, fire  rapidly. * Disks sense slight pressure, continually  firing. 1. Pain afferents enter chord  laterally due to small size. 2. Synapse immediately. 3. Enter dorsal horn. 4. Secondary afferents cross to  opposite side of the spinal  cord. 5. Ascent in the spinothalamic  tract. 6. Spinothalamic system enters  VPL 7. Synapse 8. Carried to cortex by  thalamacortical neurons. * C fibers carry slow because they  are unmyelinated. *A-delta fibers carry fast
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Unformatted text preview: 1. Head movement causes fluid in the three semicircular canals to move the gel and pull the hair cells. 2. Vestibular info is relayed to vestibular nucleus of the medulla, via cranial nerve VIII, the auditory nerve. 3. Axons leaving the vestibular nucleus synapse with neurons associated with cranial nerves that control eye movements. 4. Some axons from the vestibular nucleus go to the cerebellum, reticular formation and spinal cord, which assist in postural reflexes and maintain balance. 5. Other axons from the vestibular nucleus synapse with the nucleus of the solitary tract and cranial nerve X, which has connection to the stomach and other areas. 6. Other axons leaving the vestibular nucleus go to the thalamus and then vestibular sensory cortex in the temporal lobe....
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