ANATOMY AND PHYSIOLOGY

Question 1

what does the external ear consist of?

Answer 1

Auricle - eardrum, meatus

Question 2

what does the middle ear consist of?

Answer 2

malleus, incus, stapes

Question 3

what does the internal ear consist of?

Answer 3

semi-circular canals, vistibuli, cochlea

Question 4

what are some auditory dysfunctions that occur in the inner ear?

Answer 4

hearing-loss, tinnitus, hyperacusis

Question 5

what are some of the vestibular dysfunction?

Answer 5

dizziness, vertigo, unsteadiness, imbalance.

Question 6

what makes up the vestibular part of the inner ear?

Answer 6

saccule, utricle and 3 semi-circular canals

Question 7

what makes up the otoliths?

Answer 7

saccule and utricle

Question 8

what do the otoliths sense?

Answer 8

linear head acceleration

Question 9

what do the semi-circular canals sense?

Answer 9

angular head acceleration

Question 10

what fluid runs through semi circular canals?

Answer 10

endolymph

Question 11

where does the endolymph follow into?

Answer 11

Ampula

Question 12

what does the endolymph movement cause to move?

Answer 12

stereocilia which leads to release of NT - sending info to brain

Question 13

what are the general functions of the otoliths?

Answer 13

Detect forward and backward movement & gravitational forces

Question 14

function of utricle and saccule?

Answer 14

detection of movement in horizontal plane

detection of movement in vertical plane

Question 15

what is type 1 hair cell?

Answer 15

chalice cells, 1 afferent nerve calyx, “true” receptors (90% of afferents)

Question 16

what are type 2 hair cells?

Answer 16

cylindrical cells, several afferent & efferent nerve endings (10% afferent)

Question 17

what are kinocillium hairs?

Answer 17

thicker and longer than stereo cilia

secured to cell by basal body

Question 18

what are stereocillia cells?

Answer 18

5-110 thin
Height increases across cell to kinocillium
shorter in macula, in Cristae up to 36microns

Question 19

how is vestibuli stimulated?

Answer 19

a force parallel to the surface of sensory epithelium, bisects the bundle of steroecillia & pass directly through kinocillium - maximal stimulus

Question 20

what is vestibule-ocular reflex?

Answer 20

responsible for maintaining eye fixation during head movement, obtains object in fovea
VOR responses to head movement with eye movement that is equal in magnitude but opposite in direction

Question 21

what is the vestibulo-ocular arc?

Answer 21

neuron from semi-circ > neuron in vest. nuclei transmits info to eye muscle nuclei > eye motor neurone

Question 22

what is vestibulo-spinal reflex?

Answer 22

coordinate head and neck movement with trunk & body - goal of maintaining head in upright position

Question 23

what is lateral vestibulospinal responsible for?

Answer 23

postural changes to compensate for tilts and body movements

Question 24

what is medial vestibulo-spinal responsible for?

Answer 24

stabilises head position during walking

Question 25

what is vestibulo-collic reflex?

Answer 25

acts on neck musculature to stabilise head with body movements

Question 26

what is vestibulocerebellum?

Answer 26

functions as adaptive processor and readjusts vestibular input through inhibition

Question 27

what are the ascending connections from vestibular nuclei?

Answer 27

Anterior horn cells of spinal cord, via vestibule-spinal tract 
cerebellum 
contralateral vestibular nuclei 
cranial nerve 3,4,6
pontine reticular formation