Neuro test 3

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Neuro test 3
2011-06-15 01:11:58
cranial nerves

cranial nerves
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  1. LMNs of Trochlear N
    • in trochlear nucleus (inferior colliculus)
    • decusate to form nerve
    • innervate superior oblique M (depress eye)
  2. lesions of trochlear N
    • trouble keeping eye in down and inward position
    • ex: while walking down stairs
  3. LMNs of Abducens N
    • in abducens nucleus in lower pons (facial colliculus in rhomboid fossa)
    • innervate ipsilateral lateral rectus M (abduction)
  4. lesion of abducens N
    • flaccid paralysis of ipsilateral lateral rectus
    • inable to abduct eye
    • medial strabismus
    • double vision- diplopia
  5. Oculomotor N
    • originates from oculomotor nuclear complex (midbrain- superior colliculus)
    • edinger-westphal nucleus (autonomic, preganglionic parasympathetic fibers)
    • E-W neurons terminate in ciliary ganglion
  6. E-W nurons of oculomotor nerve innervate:
    • constrictor pupillae M
    • cilliary Ms
  7. Oculomotor N thru oculomotor nucleus innervates:
    • superior rectus
    • inferior rectus
    • medial rectus
    • inferior oblique
    • levator palpebra superioris
  8. papillary light reflex
    • contraction of BOTH pupils due to increased light on a single retina
    • afferent limb: II N thru optic tract and superior brachium to pretechtal nucleus to E-W nucleus
    • efferent limb: E-W nucleus to ciliary ganglia to constrictor pupilla
    • has both direct and consensual response
  9. Accommodation Reflex
    • shifing fron distant to near target
    • requires convergence, accommodation, and pupillary constriction of both eyes by III N
  10. pathway for accommodation reflex
    retinal fibers to occipital lobe to superior colliculus to either occulomotor nucleus of III N or E-W nucleus of III N

    these then innervate medial rectus (convergence), ciliary M (accommodation), and constrictor pupillae (pupillary constriction)
  11. lesions of oculomotor N
    • unilateral lesion would cause:
    • 1. ipsilateral paralysis of Ms causing droopy eyelid (ptosis) and lateral strabismus
    • 2. no papillary light reflex
    • 3. no accommodation reflex
  12. Weber's syndrome
    • caused by loss of blood to anterior midbrain
    • lesion of basal part of cerebral peduncle
    • interupts oculomotor (III) N and descending motor fibers of cerebral crus
    • RESULT: III N lesion, contralateral spastic hemiplegia
  13. LMNs of trigeminal N
    • originate from trigeminal motor nucleus (upper pons)
    • bilateral innervation to:
    • 1. Ms of mastication
    • 2. tensor veli palatini
    • 3. tensor tympani
    • 4. mylohyoid
    • 5. anterior belly of digastric
  14. trigeminal N lesion
    • flaccid paralysis
    • deviation of the mandible towards the side of paralysis
  15. Facial N- Somatosensory fibers
    • in geniculate ganglion
    • innervate skin of external ear, wall of external auditory canal, external surface of tympanic membrane
  16. pathway of Facial N somatosensory fibers
    spinalV tract to spinalV nucleus to Vthalamic tract to VPM thru posterior limb of internal capsule to primary S-S cortex
  17. Facial N- Gustatory fibers
    • in geniculate ganglion
    • to taste r/c of anterior 2/3 of tongue and palate

    solitary nucleus (in medulla) thru central tegmental tract (CTT) to VPM to postcentral gyrus and insula
  18. Facial N- somatomotor neurons
    • in facial nucleus in pons (traverse facial colliculus)
    • innervate: Ms of facial expression, stapedius, posterior belly of digastric, and stylohyoid
  19. fibers to the facial motor nucles
    • corticobulbar fibers
    • bilateral to upper 1/2 of face
    • unilateral to lower contralateral 1/2 of face
    • auditory reflex for loud noise
    • somatosensory input from trigeminal N
    • causes corneal (blink) reflex
  20. Corneal (blink) reflex
    • touching the cornea causes bilateral blinking
    • afferent limb- V N
    • efferent limb- motor fibers of VII N
    • direct and consensual respons
  21. Parasympathetic fibers in the pons from Facial N
    • superior salavitory nucleus
    • postganglionic fibers thru submandibular gangion to submandibular gland, lingual gland, sublinqual gland, and labial glands
    • secretomotor
    • lacrimal nucleus
    • from pterygopalatine gangia to lacrimal, nasal, and palatine glands
    • secretomotor
  22. lesions of facial N
    • Bell's palsy
    • -paralysis of all ipsilateral Ms innervated by facial N
    • -loss of taste from ipsilateral anterior 2/3 of tongue and palate
    • -decreased salivation
    • -decreased lacrimation
    • recovery is often fast
  23. Glossopharyngeal N- somatosensory fibers
    • in superior ganglion of IX N
    • innervate: posterior 1/3 of tongue, upper pharynx, tympanic cavity, eustachian tube

    spinalV tract to spinalV nucleus to Vthalamic tract to VPM to primary S-S cortex
  24. Gag reflex
    • afferent limb- IX N
    • efferent limb- X N, XII N, and V N
    • touching posterior 1/3 of tongue/pharynx causes gaging
  25. Glossopharyngeal N- gustatory neurons
    • in inferior ganglion of IX N
    • thru lingual br of IX N to posterior 1/3 of tongue to solitary nucleus (in medulla) thru CTT to VPM to parietal lobe and insula
  26. Glossopharyngeal N- General Visceral Afferent neurons
    • in inferior ganglion of IX N
    • to r/c in carotid sinus and carotid body to solitary tract to solitary nucleus to visceral centers in the reticular formation
  27. Glossopharyngeal N - somatomotor fibers (LMNs)
    • in nucleus ambiguus (medulla)
    • innervate stylopharyngeus
    • bilaterally innervated
  28. Glossopharyngeal N- parasympathetic fibers
    • in inferior salavitory nucleus to otic gangion
    • secretomotor for parotid gland
  29. lesions of glossopharyngeal N
    • rare
    • loss of gag reflex from ipsilateral tongue
    • decrease taste from posterior tongue
    • decrease salivation
  30. Vagus N- somatosensory neurons
    • in superior gangion of X N
    • innervate: skin of external ear, lower pharynx, larynx, upper esophagus, external auditory canal

    spinal V tract to spinal V nucleus to V thalamic tract to VPM to primary S-S cortex
  31. Vagus N- gustatory neurons
    • in inferior ganglion of X N
    • to taste receptors on epiglottis

    solitary nucleus thru CTT to VPM to paietal and insulal lobes
  32. Vagus N- general visceral afferent neurons
    • in inferior ganglion of X N
    • aortic arch baro and chemo r/cs, and distension of hollow organs thru the solitary tract to the solitary nucleus
  33. Vagus N- somatomotor neurons
    • in the nucleus ambiguus
    • forms the Vagus N and cranial root of XI N (to palate and larynx)
    • innervates: all palate Ms except tensor veli palatini, all pharynx Ms except stylopharyngeus, all intrinsic larynx Ms, upper esophagus
    • bilateral corticobulbar innervation
  34. Vagus N- parasympathetic neurons
    in dorsal motor nucleus of X N (medulla) to terminal/intramural ganglion near organs to visceral effector cells
  35. Vagus N lesions
    • unilateral
    • ipsilateral paralysis
    • horseness of voice
    • difficulty breathing
    • difficulty swallowing
    • uvula deviates away from lesioned side
    • bilateral
    • death from vocal folds adducting together
  36. Spinal Accessory N- Spinal root
    • in spinal accessory nucleus (C1-5)
    • enters cranial vault thru foramen magnum
    • joins cranial root prior to exiting jugular foramen (then cranial root joins with X N)
    • to SCM and trap
  37. lesion of XI N
    unilateral lesion would cause ipsilateral paralysis of SCM and trap
  38. Hypoglossal N- LMNs
    • in hypoglossal nucleus in medulla
    • innervates Ms of tongue except palatoglossus M
    • contralateral innervation
  39. hypoglossal N lesions
    unilateral lesion: ipsilateral paralysis of tongue, tongue would deviate toward lesioned side
  40. Medullary center of cerebrum
    • core of white matter
    • projection, commissural, and association fibers
  41. projection fibers
    • thru internal capsule
    • connect cerbrum to outside structure
    • corticopedal fibers- into cerebrum
    • corticofugal fibers- out of cerebrum
  42. Commissural fibers
    • connect the 2 hemispheres
    • corpus callosum
  43. association fibers
    • in a single hemisphere
    • superior longitudinal fasciculus (connects motor and sensory language areas)
  44. neocortex
    • 6 layers
    • found in association areas
  45. paleocortex
    5 layers, found in uncus (olfactory areas)
  46. archicortex
    3 layers, found in hippocampus
  47. neurons of the cerebrum
    • mainly pyramidal cells
    • giant pyramidal cells (BETZ cells) found in precentral gyrus
    • stellate cells
    • fusiform cells
  48. afferent fibers terminate in which layers of cortex
    layers 1-4
  49. afferent fibers from the thalamus terminate in which layers of cortex
    layer 4
  50. area of cortex with best layer 4?
    primary sensory cortical areas
  51. corticofugal fibers come from which layers of cortex?
    layers 5-6
  52. Prefrontal cortex
    • frontal lobe areas not involved in motor activity
    • involved in: abstract thinking, descion making, judgement, behavior, reaction to experiances
  53. bilateral lesion of prefrontal cortex
    • causes difficulty making good descions
    • laxidasical behavior
    • dishonesty
  54. cerebral dominance
    • language has a dominat hemisphere (usually left)
    • lesion would cause aphasia (loss of language)
  55. Broca's area
    • opercular and triangular portions of inferior frontal gyrus
    • -44 and 45
    • motor area of language (speech, writing, and signing)
  56. Sensory language area
    • posterior auditory association cortex (Wernicke's area)
    • supramarginal and angular gyrus
    • allows interpretation os language
  57. lesion of Broca's area
    • impaired ability to speak fluently
    • can comprehend language, trouble responding
  58. Sensory language area leasion
    • inability to comprehend language
    • con spontaneously speak, cant correct mistakes
  59. Superior longitudinal fasciculus lesion
    • good comprehesion
    • spontaneous speach
    • unable to correct mistakes
    • poor repetition, response to questions, reading out loud
  60. posterior spinal As
    • brach of vertebral As
    • descend near dorsal lateral sulcus
    • lie in subarachnoid space
  61. anterior spinal A
    • 2 braches off vertebral As- fuse together
    • descends along ventral median fissure
  62. arterial vasa corona
    • in pia mater around cord
    • supplied by spinal As
    • sulcal branches- enter cord thru ventral median fissure
    • penetrating branches- to peripheral cord
  63. Anterior spinal A supplies:
    anterior 2/3 of the cord
  64. posterior spinal As supply
    posterior 1/3 of cord
  65. Segmental As give off spinal branches:
    • replenish the blood in spinal As as they descend the cord
    • enter thru IVF
    • anterior radicular to anterior spinal A (9-12)
    • posterior radicular to posterior spinal As (12-14)
    • most vulnerable cord segments to occlusion- T1-4, L1
  66. Posterior inferior cerebellar As
    • give of medullary branches
    • occlusions cause:
    • lateral medullary syndrome (Wallenburg's syndrome)
    • -loss of pain and temp from contralateral body
    • -loss of pain and temp from ipsilateral face
  67. Basilar A
    formed from the fusing of the two vertebral As
  68. Anterior inferior cerebellar A
    to cerebellum
  69. internal auditory A
    • thru internal auditory meatus to inner ear
    • occlusions would cause ipsilateral deafness
  70. pontine As
    to basilar pons
  71. superior cerebellar As
    to cerebellum and superior cerebellar peduncles
  72. posterior cerebral As
    • terminal br of basilar A
    • lesion would cause cortical blindness of contralateral visual field
  73. internal carotid A
    many branches, anatomoses with basilar A thru posterior communicating As
  74. hypophyseal branches
    to pituitary gland
  75. opthalmic A
    to eyeball and orbit
  76. anterior chordial A
    • to uncus, amygdala, and optic tract
    • occlusion would cause contralateral hemianopsia
  77. anterior cerebral As
    • to corpus callosum
    • cingulate gyrus
    • frontal and parietal gyrus
    • orbial gyrus
    • olfactory bulb and tract
    • paracentral lobule
    • lesions would cause contralateral spastic paralysis of lower extremities
  78. Middle cerebral A
    • largest branch
    • thru lateral sulcus to lenticulostriate As
    • to auditory cortex
    • motor cortex
    • premotor- frontal eye field
    • primary somatosensory
    • dominant language area