Lecture 29: Neuroanatomy of Auditory and Vestibular Sytems

Question 1

functions of the vestibular system

Answer 1

• transduces and interprets head movements
• maintains positioning of visual axes when head is moving (vestibulo-ocular reflex)
• sends motor commands to trunk and limb muscles to maintain balance

Question 2

vestibular nuclei in the brainstem receive info from ____ on head movement and info about muscle firing from the _____

Answer 2

organs of balance, cerebellum

Question 3

what part of the brain coordinates timing of movements

Answer 3

cerebellum

Question 4

lesions of CN ____ or ______ nuclei lead to distruptions in stance, head posture, balance

Answer 4

CN VIII, vestibular nuclei

Question 5

damage to the vestibular nuclei can lead to loss of ____ muscle tone

Answer 5

extensor

Question 6

what are the vestibular organs

Answer 6

• semicircular ducts
• utricle, saccule
• vestibular nerve

Question 7

what are the cochlear organs

Answer 7

• cochlear duct and cochlear nerve

Question 8

the membranous labyrinth contains _______
the regions b/w membranous ducts and walls of bony labyrinth contains ________

Answer 8

endolymph, perilymph

Question 9

the vestibular and cochlear apparatus rely on mechanical displacement of _______ receptors by fluid

Answer 9

mechanoreceptors
fluid is a derivative of lymph

Question 10

vestibular organs are _______ sensory apparatuses

Answer 10

peripheral

Question 11

what is the function of the utricle

Answer 11

monitor and activate response to linear acceleration of horizontal movements (side to side, front to back)

Question 12

what is the function of the saccule

Answer 12

monitors and activates response to linear acceleration of ventral movements (up+down)

Question 13

what is the function of the three semicircular ducts

Answer 13

monitor and respond to rotation of head in all places

Question 14

the semicircular duct _____ cells transduce angular acceleration

Answer 14

hair

Question 15

when stereocilia move towards kinocilium, hair cells ______, increasing firing rate

Answer 15

depolarize

Question 16

when stereocilia are deflected away from kinocilium, hair cells ______, decreasing firing rate

Answer 16

hyperpolarize

Question 17

hair cells will depolarize on the side of the head towards which the person is turning, causing an _______ in firing rate of hair cells

Answer 17

increase

Question 18

hair cells will _______ on the side of the head from which the person is turning, causing a _____ in the firing rate of hair cells

Answer 18

hyperpolarize, decrease

Question 19

lesions of what would cause perception that the head is constantly moving when it isn’t

Answer 19

lesions of the vestibular portion of CN VIII, the vestibular apparatus or vestibular nuclei