Lecture 12- Vestibular System Flashcards
Two parts of the vestibular system
Inner ear (senses movement)
Brain (CN VIII, controls eye mvmnt)
What does the cochlea do?
Hearing
What is the Utricle/saccule responsible for?
linear acceleration and gravity
What are the three semicircular canals responsible for?
vestibular movement and rotation
How do the hair cells generate action potentials?
increase activity when bent one direction, decrease activity when bent in the other direction
Where are the vestibular crystals located?
Utricle and saccule
If the head leans naturally to the left…
Increase in cilia firing on left, decrease on right
brain will correct posture by increasing muscle tone on the left
Damage to cilia on the left will cause…
body to think it is tilting to the right
overcorrection and lean to the left
Eyes will drift left and snap right
In peripheral vestibular lesions, the head will tilt and eyes will snap…
Head will tilt towards the lesion, eyes will snap away from the lesion
Pendular nystagmus is?
A congenital abnormality; eyes move equal speed in each direction
What is the role of the cerebellum in vestibular system
To inhibit vestibular nuclei
In paradoxical vestibular, which direction will the patient lean and eyes snap?
Leans to the opposite side of infection, eyes, eyes will snap in the direction of the lesion
Bilateral vestibular disease symptoms
No head tilt or nystagmus, decreased posture, crouch and swagger, wide head excusrsions, cannot induce nystagmus
