Neuro Exam 3.5

  1. What are the parts of equilibrium and balance?
    • vestibular system
    • equilibrium triad
  2. What is the function of the vestibular system?
    detects changes in motion and position of the head (respect to gravity and horizon)
  3. Where does information come into the vestibular system from?
    equilibrium triad
  4. What happens when the equilibrium triad is not in sync?
    problems with equilibrium
  5. What are the parts of the equilibrium triad?
    • vision
    • proprioception
    • vestibular system
  6. Which cranial nerve is associated with vision?
    CN II: Optic Nerve
  7. What is the dominant sensation in humans?
  8. What characteristics of vision must be able to be maintained in order to have normal equilibrium?
    constant, coordinated eye gaze
  9. What determines head position?
    plane of vision; adjust head to coordinate gaze
  10. VOR:
    vestibulo-ocular reflex
  11. What is the VOR?
    keeps your eyes pointed in a particular direction despite body movement
  12. Which column deals with proprioception?
    dorsal column
  13. What is proprioception?
    body position sense in context to gravity
  14. What does proprioception influence?
    muscle tone of neck to maintain plane of vision
  15. Which cranial nerve is associated with vestibular system?
    CN VIII: Vestibulochochlear nerve
  16. Where is the vestibular system found?
    inner ear
  17. What does the inner ear detect?
    motion and position changes of the head
  18. What anatomy makes up the vestibular system?
    • bony labyrinth
    • membranous labyrinth
  19. Where is the bony labyrinth located?
    lateral portion of petrous portion of temporal bone
  20. How many parts make up the bony labyrinth?
  21. What are the 3 parts of the bony labyrinth?
    • cochlea
    • vestibule
    • semicircular canals/ducts
  22. What does the cochlea do?
  23. What is the vestibule?
    small oval chamber composed of utricle and saccule
  24. What do the utricle and saccule detect?
    linear acceleration
  25. How many semicircular canals are there?
  26. What are the 3 semicircular canals?
    • anterior
    • posterior
    • lateral
  27. What do the semicircular canals detect?
    angular acceleration
  28. How are the semicircular canals arranged?
    set at right angles to occupy 3 planes of space
  29. What shape do the semicircular canals form?
    2/3 of a circle
  30. Where do the semicircular canals lie?
    posterior to vestibule
  31. What is the diameter of the semicircular canals?
    about 1.5mm, except at ends where they are dilated
  32. What are the dilated ends of the semicircular canals referred to as?
  33. Ampulla:
    bulge along semicircular canals that contain hair cells of semicircular canals
  34. Which way do the ampulla face?
    towards the vestibule
  35. Perilymph:
    fluid w/in the bony labyrinth
  36. Where is the membranous labyrinth?
    inside bony labyrinth
  37. What is the membranous labyrinth?
    system of sacs and ducts that communicate w/ and are suspended w/in the bony labyrinth
  38. What type of fluid in in the membranous labyrinth?
    endolymph--characteristics are identical to perilymph
  39. What are the 3 parts of the membranous labyrinth?
    • utricle and saccule
    • 3 semicircular ducts
    • cochlear duct
  40. Where are the utricle and saccule found?
    vestibule of bony labyrinth
  41. What system are the utricle and saccule a part of?
    vestibular system
  42. Do the utricle and saccule communicate with each other?
  43. What system are the semicircular ducts a part of?
    vestibular system
  44. Where are the semicircular ducts found?
    in semicircular canals
  45. What are the enlarged ends of the semicircular ducts referred to as?
  46. What is the sensory area of the ampulla?
    crista ampullaris
  47. Crista ampullaris:
    sheet of hair cells of the semicircular canals
  48. Where is the cochlear duct?
    sits in cochlea (part of bony labyrinth)
  49. What is the cochlear duct responsible for?
    hearing sound
  50. What is the functional area of the semicircular canals?
    crista ampullaris
  51. Cupula:
    gel that spans the lumen of the canal w/in the ampulla; cilia project into cupula
  52. What do the cilia of the cupula make up?
    sensitized hair cells (75-100 stereocilia/microvilli)
  53. Kinocilium:
    one tall (large) cilium per each hair cell that detects the direction in which the hair cells bend as a result of head movement
  54. What is another name for Kinocilium?
    true cilium
  55. What does movement of the head cause?
    endolymph to move and bend the hair cells
  56. What happens when the hair cells bend toward the kinocilium?
    • cell membrane stretches, opening K channel (K influx)
    • depolarization that results in opening of voltage-gated Ca channels (Ca influx)
    • Ca influences exocytosis process
  57. What happens if the hair cells bend away from kinocilium?
    hyperpolarizaiton (inhibits cell)
  58. What happens if the hair cells bend toward kinocilium?
    depolarization (excitatory receptor potential)
  59. What does depolarization cause?
    membrane to release NT
  60. What does the NT influence?
    1st order sensory neurons in equilibrium pathway (CN VIII)
  61. What type of potential occurs at the 1st order sensory neurons in the equilibrium pathway?
    • generated potential (type of graded potential)
    • AP occurs w/ enough depol
  62. What does the crista ampullaris respond to?
    angular acceleration and deceleration, but not constant movement
  63. While rotation excites the hair cells of one canal, it:
    inhibits the hair cells of contralateral partner
  64. All bending of hair cells occurs in:
    same direction
  65. What do the utricle and saccule contain?
    hair cells similar to the semicircular canals
  66. otoliths:
    tiny crystals of calcium carbonate that move in the endolymph function to add energy dissipation and amplify the message for movement
  67. What do the utricle and sccule together detect?
    linear acceleration (moving forward/backward)
  68. How is the utricle positioned?
  69. What does the utircle detect?
    • horizontal movement
    • lateral bending of head/neck
  70. How is the saccule positioned?
  71. What does the saccule detect?
    • vertical movement
    • flexion/extension of head/neck
    • up and down changes
  72. There is some overlap b/w the crista amullaris/utricle/saccule--but for the most part:
    each is responsible for the functions listed
  73. What are hair cells?
    modified neurons
  74. Hair cells depolarize to dump:
    NT into synaptic cleft, which influences receptor organ at distal end of 1st order neuron (CN VIII)
  75. Where are the cell bodies of hair cells located?
    vestibular ganaglia
  76. Where does CN VIII go to synapse w/ 2nd order?
  77. Where is nystagmus seen?
  78. Nystagmus:
    movement of eyes beginning w/ slow movement to one side then rapid movement in opposite direction
  79. What are the stages of nystagmus?
    • rapid phase
    • slow phase
  80. What is the rapid phase called?
  81. What is the slow phase called?
    slow component
  82. How are nystagmus named?
    according to the rapid phase direction (right or left)
  83. Nystagmus is malfunctioning vestibular system including problems with:
    • inner ear
    • CN VIII
    • vestibular ganglia
    • vestibular nuclei in pons
    • cerebellum
  84. What is caloric nystagmus based on?
    temperature in inner ear
  85. How do you test for caloric nystagmus?
    use cold or warm water in syringe
  86. What does the water cause the endolymph to do?
    move w/in semicircular canal more than saccule and more than utricle
  87. As the endolymph moves in response to water temperature, what do the hair cells do?
    move and result in nystagmus
  88. What does cold water in the R ear do?
    • nystagmus of L
    • contralateral
  89. What does warm water in R ear do?
    • nystagmus of R
    • ipsilateral
  90. If there is no nystagmus with this test, there is a possible:
    neurological issue going on
  91. Rotational nystagmus:
    • as head and body pivot/circle, the eyes attempt to fix on an object in space (slow component)
    • as head and body continue to circle, the eyes snap quickly in the direction that the head is circling (saccade)
  92. The action from rotational nystagmus is similar to what happens when you watch:
    telephone poles from a moving train: saccade occurs in direction train is moving
  93. What happens to eye movements during rotational nystagmus?
    repeat throughout duration of circling
  94. Which way does nystagmus occur in rotational nystagmus?
    direction you spin
Card Set
Neuro Exam 3.5
review of neuro lecture 5 for exam 3