inner ear

Question 1

how are waves of movement created in the fluid of the inner ear

Answer 1

vibration from the stapes at the oval window

Question 2

what cells are housed in the membranes of the inner ear

Answer 2

special hearing and balance

Question 3

what are the 2 labyrinths in the inner ear

Answer 3

bony and membranous

Question 4

the bony labyrinths are surrounded by what

Answer 4

otic capsule

Question 5

where is the otic capsule located

Answer 5

petrous temporal bone

Question 6

describe the bony labyrinth

Answer 6

system of canals filled with perilymph

Question 7

what is perilymph similar to

Answer 7

extra-cellular fluid

Question 8

the bony labyrinth contains what

Answer 8

cochlea
vestibule
semi-circular canals

Question 9

what is the membranous labyrinth

Answer 9

continuous system of ducts and sacs inside the bony labyrinth

Question 10

the membranous labyrinth is suspended in what and contains what

Answer 10

suspended in perilymph and contains endolymph

Question 11

what is endolymph similar to

Answer 11

K+ rich intra-cellular fluid

Question 12

what is the function of perilymph and endolymph

Answer 12

conduct sound vibrations and respond to mechanical forces (movement and acceleration)

Question 13

the cochlea houses what cells

Answer 13

special cells of hearing

Question 14

vibration is passed from the footplate of the stapes to what

Answer 14

membrane of oval window

Question 15

when the oval window vibrates, a wave of movement passes where

Answer 15

perilymph of the scala vestibuli

Question 16

where does the scala vestibuli ascend to

Answer 16

top of the shell shape of the cochlea

Question 17

what is the name of the scala vestibuli at the top of the cochlea

Answer 17

helicotrema

Question 18

describe the path of vibrations from the oval window

Answer 18

movement in perilymph of scala vestibuli, passes in scala vestibuli to top of cochlea (helicotrema) then down other side in scala tympani to base of cochlea at the round window

Question 19

what happens to vibrations at the round window

Answer 19

nothing attached so they dissipate into middle ear

Question 20

what happens as the wave of vibration passes through the perilymph

Answer 20

presses on membranous labyrinth (cochlear duct) which deforms the membrane which is detected by the special cells within the membrane

Question 21

what is the name of the membrane of the cochlear duct

Answer 21

tectorial membrane

Question 22

the cochlear duct lies between the scala vestibuli and

Answer 22

the scala tympani

Question 23

what cells in what in the cochlea detect movement and transform it into electrical energy (nerve impulse)

Answer 23

cells in the spiral organ (organ of corti)

Question 24

the nerve impulse from the organ of corti is passed where

Answer 24

cochlear nerve - part of CN VIII

Question 25

the CN VIII carries impulse to where

Answer 25

auditory cortex of brain

Question 26

why are the scala called so

Answer 26

stairs - you ascend the vestibular cells to the top of the cochlea and then descend via the tympanic staircase

Question 27

where do the semicircular canals lie in relation to the vestibule

Answer 27

posterior and lateral to the vestibule

Question 28

what are the 3 semi-circular canals

Answer 28

anterior posterior and lateral

Question 29

describe the shape of the semi-circular canals

Answer 29

each canal is 2/3 of a circle and 1.5mm in diameter

Question 30

what are the orientations of the semi-circular canals

Answer 30

anterior and posterior are at right angles | lateral is horizontal

Question 31

which semi-circular canal is horizontal

Answer 31

lateral

Question 32

what do the semi-circular canals contain

Answer 32

semi circular ducts of the membranous labyrinth

Question 33

the semi-circular ducts are continuous with what

Answer 33

semi-circular ducts

Question 34

each semi circular duct swells at the end forming a

Answer 34

ampullae

Question 35

what is the vestibule

Answer 35

area of bony labyrinth that the oval window opens into, which communicates with the cochlea and semicircular canals

Question 36

where do the semi-circular ducts house motion sensitive cells

Answer 36

ampullae

Question 37

each ampulla houses what

Answer 37

equilibrium receptor called crista ampullaris

Question 38

what does crista ampullaris respond to

Answer 38

angular (rotational) movements of the head

Question 39

how long is the vestibule

Answer 39

5mm

Question 40

what is found inside the vestibule

Answer 40

2 membranous sacs; utricle and saccule

Question 41

what do the utricle and saccule contain

Answer 41

equilibrium receptors called maculae

Question 42

what do maculae respond to

Answer 42

pull of gravity and changes in head position

Question 43

motion is detected by waves of movement through the endolymph inside what

Answer 43

ampullae utricle sacule

Question 44

nerve impulses from the receptors in the ampullae, utricle and saccule to what

Answer 44

into the vestibular part of CN XIII

Question 45

what are otoliths

Answer 45

minute pieces of bone that sit on the receptor cells and move in response to the movement of the endolymph

Question 46

the vestibulocochlear nerve passes from what part of the brainstem

Answer 46

pons

Question 47

is the cochlear or vestibular nerve more superior

Answer 47

cochlear nerve superior

Question 48

what brain foramen does the vestibulocochlear nerve pass through

Answer 48

internal acoustic meatus

Question 49

the main supply to the inner ear is from what

Answer 49

internal auditory (labyrinthine)

Question 50

what branches does the internal auditory artery give

Answer 50

common cochlear and vestibular arteries

Question 51

the internal auditory artery is a branch of what in 80% of people or what

Answer 51

branch of anteroinferior cerebellar artery in 80% of people | or basilar artery