part 3

Question 1

location and shape of utricle

Answer 1

horizontal and closer to semi-circular canals

Question 2

location and shape of saccule

Answer 2

vertical and closer to cochlea

Question 3

what does saccule do?

Answer 3

linear acceleration; gravity

Question 4

what is macula

Answer 4

surface that contains haircells
- its flat and not cristae anymore

Question 5

what is otoconia

Answer 5

calcium carbonate crystals

Question 6

what is striola

Answer 6

central region of macula

Question 7

otolithic membrane’s specific gravity

Answer 7

is higher than that of endolymph because of the otoconias in the otolith organs (stones added to gel so it is heavier)

Question 8

kinocilia of utricle

Answer 8

towards striola

Question 9

kinocilia of saccule

Answer 9

away from striola

Question 10

utricle

Answer 10

horizontal linear acceleration and static head tilt
- encodes linear accelerations (not angular)

Question 11

saccule

Answer 11

vertical linear acceleration
encodes jumping up and down, going on elevator

Question 12

otolith organs encode

Answer 12

linear acceleration and static tilt

Question 13

anterior posterior acceleration and lateral acceleration encoded by

Answer 13

utricle (b/c in horizontal plane)

Question 14

occipital-caudual accelerations encoded by

Answer 14

saccule because in vertical plane

Question 15

what are occipital-caudual accelerations

Answer 15

roll
yaw- shake head no
pitch- shake head yes

Question 16

static upright tilt encoded by

Answer 16

saccule

Question 17

static pitch and roll encoded by

Answer 17

utricle

Question 18

what is not encoded by otolithic organs

Answer 18

static yaw (both motion and static position)

Question 19

forward acceleration

Answer 19

sterocillia move toward kinocilium increase firing rate

Question 20

car in reverse (backward acceleration)

Answer 20

sterocilium move away from kinocilium and decrease firing rate

Question 21

head upright (upright tilt)

Answer 21

resting firing rate

Question 22

head tilted forward (looking down)

Answer 22

otoconia move down bending sterocilium away from kinocilium decreasing firing rate;
- utricle encode static tilt, SCC encode motion

Question 23

Blood supply from otolithic organs comes from where

Answer 23

Basilar artery or Anterior inferior cerebellar artery (AICA)

Question 24

anterior vestibular artery

Answer 24

from internal auditory artery (labryrinthine artery) utricle, AC (anterior SCC) and HC (horizontal SCC)

Question 25

posterior vascular artery

Answer 25

from common cochlear artery - saccule, PC

Question 26

1st neuron

Answer 26

scarpa ganglion - internal auditory ear canal, close to pontocrebellar angle; axons bundled together in 15-20K a vestibular nerve fibers leading to the vestibulo-cochlear nerve

Question 27

2 branches of the vestibulo-cochlear nerve

Answer 27

superior vestibular- Utricle, AC, HC inferior vestibular- Saccule, pc

Question 28

2nd neuron

Answer 28

innervation- vestibular nuclear complex. vestibular nerve bifrucates at pontomedullary junction into 1. primary superior vestibular afferents and 2. primary inferior vestibular afferents

Question 29

commisural fibers

Answer 29

L & R vestibular nuclear complexes connected with these fibers through which information is projected contralaterally

Question 30

vestibular pathway 3rd neuron

Answer 30

vestibular end organs send info that travels to the vestibular nuclei in the brainstem

Question 31

what are the main projections of the vestibular nuclei to

Answer 31

spinal cord (controls head and body postion) 3 extraocular motor nuclei (III IV VI, control eye movement VOR) Cerebellum (coordinates postural adjustments) Thalamus (eventually reaching cortex & Conscious perception of movement and gravity) and the emetic pathway (causing vomiting