Exam 2 Review

Question 1

Static Labyrinth

Answer 1

• Utricle, saccule
• Uses otolithic membrane (crystal) for gravito-intertial acceleration
• Linear acceleration

Question 2

Kinetic Labyrinth

Answer 2

• Semicircular ducts (ampulla)
• Angualr acceleration

Question 3

Lateral Vestibular Nuclei

Answer 3

• Vestibulospinal reflex (VSR): stabilize body, limb
• LVST
  
  • AICA > PICA > ASA
  • To SC and cerebellum
  • UNCROSSED

Question 4

Medial Vestibular Nuclei

Answer 4

• VOR: MLF
• VCR: MVST (AICA)

Question 5

VOR

Answer 5

• Input from the L lateral semicircular duct will excite the contralateral lateral rectus and ipsilateral medial rectus, and inhibit the ipsilateral lateral rectus and contralateral medial rectus.
• Superior vestibular nucleus sends inhibitory projections via MLF to oculomotor motoneurons of the ipsilateral LEFT EYE lateral rectus (to inhibit left lateral abduction) and crossed to also inhibit contralateral RIGHT EYE medial rectus
• Medial vestibular nucleus sends axons via MLF crossed excitatory fibers to the contralateral CN 6 nucleus excite the RIGHT EYE lateral rectus and also sends axons back over to excite ipsilateral LEFT EYE medial rectus

Question 6

4 Clinical Signs of Vestibular Damage

Answer 6

• Vertigo
• Ataxia: tuncal ataxia (impaired body position)
• Nystagmus: oscillating eye movements
• Nausea/vomiting

Question 7

BPPV

Answer 7

• misplaced otocconia (ear crystal) floating in semicircular ducts
• Canalithiasis: in semicircular duct
• Cupulolithiasis: adheres to cupula