vestibular system

Question 1

what are the three major functions of the vestibular system

Answer 1

sensation of motion and spatial orientation
upright posture via input to areas of axial muscle control
stabilize the eyes in space during head movements

Question 2

the ___ ___ contains cells that transduce information about how body is situated in space

Answer 2

bony labyrinth

Question 3

the ___ ___ is enclosed within the bony labyrinth

Answer 3

membranous labyrinth

Question 4

the membranous labyrinth floats in _____ and the labyrinth is filled with _____

Answer 4

perilymph; endolymph

Question 5

what are the five receptor organs located within the labyrinth

Answer 5

3 semicircular canals (located in different planes)
2 otolithic organs

Question 6

___ acceleration is a change in velocity without a change of direction

Answer 6

linear

Question 7

stereocilia are embedded in gelatinous substance called the

Answer 7

otolithic membrane

Question 8

calcium carbonate crystals that sit on top of the otolithic membrane

Answer 8

otoconia

Question 9

_____ arranged so that vertical stimuli activate/inhibit the

Answer 9

saccules

Question 10

______ arranged so that horizontal stimuli activate/inhibit the

Answer 10

utricles

Question 10

hair cells of utricle and saccule arranged in such a way that a set of the hair cells will be maximally depolarized, while another will be maximally ____

Answer 10

inhibited

Question 11

what three planes are the semicircular canals situated in

Answer 11

anterior, posterior, horizontal

Question 12

each canal has an ____ at its base

Answer 12

ampulla

Question 13

each ampulla contains ___ with hair cells with the stereocilia embedded in a gelatinous substance called the ____

Answer 13

crista, cupula

Question 14

rotation of the head leads to movement of ____ inside

Answer 14

endolymph

Question 15

when there is angular rotation of the head

Answer 15

lag after movement
endolymph moves in canal
cupula is displaced
stereocilia are moved

Question 16

movement of the hair cells in one direction; toward the _____ increases action potentials of fibers innervating hair cells

Answer 16

kinocilia

Question 17

keeps head on level plane while body moves

Answer 17

vestibulo-collic reflex

Question 18

adjust posture whole body changes position

Answer 18

vestibulo-spinal reflex

Question 19

keeps eyes in same position as head moves

Answer 19

vestibulo-ocular reflex

Question 20

simplest vestibulo ocular reflex pathway is

Answer 20

1. 8th nerve
2. vestibular nucleus (makes 2 projections)
   3 a. contralateral abducens nucleus
   b. ipsilateral oculomotor
3. motor neuron to ocular muscles
4. excitatory pathway