ear

Question 1

what are the two functions of the ear?

Answer 1

equilibrium and hearing

Question 2

detecting position of head and coordinating movement

Answer 2

equilibrium (balance)

Question 3

detecting sound waves and converting them into nerve impulses

Answer 3

hearing (audition)

Question 4

outer mass of tissue

function: collects sound waves and directs them into the auditory canal

Answer 4

auricle (pinna)

Question 5

between auricle and tympanic membrane

function: directs sound waves to the tympanic membrane

Answer 5

external acoustic meatus

Question 6

function: moves/vibrates the auditory ossicles when sounds vibrate this

• makes up the lateral portion of the middle ear (external boundary)

Answer 6

tympanic membrane (eardrum)

Question 7

what structures make up the outer ear?

Answer 7

auricle, external acoustic meatus, and tympanic membrane

Question 8

make up the medial portion of the middle ear (internal boundary)

Answer 8

oval window and round window

Question 9

ear bones (malleus, incus, stapes)

function: transmit and amplify vibrations from the eardrum to the inner ear

Answer 9

auditory ossicles

Question 10

connects with oval window and the inner ear

Answer 10

stapes

Question 11

where sound waves are transmitted to the inner ear

Answer 11

oval window

Question 12

connects middle ear with nasopharynx

function: equalize pressure in the middle ear

Answer 12

auditory (eustachian) tube

Question 13

• fill up with fluids/pus
• eardrum bulges forward
• infection may travel from throat to middle ear or vice versa via the auditory tube

Answer 13

otitis media (middle ear infection)

Question 14

when an airplane descends to a lower altitude, you may feel greater pressure in your ears, followed by a “popping” sensation, before normal pressure resumes. what happens anatomically?

Answer 14

helps equalize pressure in the middle ear by opening the auditory tube

Question 15

what structures make up the middle ear?

Answer 15

auditory ossicles and auditory eustachian tube

Question 16

spaces/cavities inside temporal bone

Answer 16

bony labyrinth

Question 17

membranous sacs/tubes that rest inside the bony labyrinth

Answer 17

membranous labyrinth

Question 18

fluid between the bony and membranous labyrinth

• inside the bony part and outside the membranous part
• the membranous labyrinth “floats” in this
• chemically similar to CSF

Answer 18

perilymph

Question 19

fluid inside the membranous labyrinth

• chemically similar to intracellular fluid
• helps conduct sound vibrations, and indirectly helps with detecting changes in position/balance

Answer 19

endolymph

Question 20

what does the bony labyrinth consist of?

Answer 20

vestibule, semicircular canals, cochlea

Question 21

oval central portion

Answer 21

vestibule

Question 22

three c-shaped spaces/canal

Answer 22

semicircular canals

Question 23

spiral chamber (means snails shell)

Answer 23

cochlea

Question 24

what does the membranous labyrinth consist of?

Answer 24

utricle, saccule, semicircular ducts, and cochlear duct

Question 25

sac inside the vestibule

Answer 25

utricle

Question 26

another sac inside the vestibule

Answer 26

saccule

Question 27

three membranous tubes in semicircular canals

Answer 27

semicircular ducts

Question 28

membranous tube inside the cochlea; responsible for hearing via the cochlear branch of CN VIII (vestibulocochlear nerve)

Answer 28

cochlear duct (scala media)

Question 29

interpreting equilibrium (balance); they transmit this information via the vestibular branch of CN VIII (vestibulocochlear nerve)

Answer 29

function of utricles, saccules, and semicircular ducts

Question 30

contain the specialized receptors in the utricle and saccule that detect static equilibrium and linear acceleration

Answer 30

maculae

Question 31

in a gel move and deflect hair cells and the vestibular branch of CN VIII sends signals to the brain

Answer 31

otoliths ("ear stones")

Question 32

contain specialized receptors located in the ampullae that detect rotational movement of the head

Answer 32

semicircular ducts

Question 33

movement of this deflects hair cells in the crista ampullaris and the vestibular branch of CN VIII sends signals to the brain

Answer 33

endolymph

Question 34

splits the cochlea into two chambers (scala vestibuli and scala tympani)

Answer 34

cochlear duct (scala media)

Question 35

- above the cochlear duct

Answer 35

scala vestibuli

Question 36

thin membrane that separates the scala vestibuli from the cochlear duct

Answer 36

vestibular membrane

Question 37

below the cochlear duct - connects to round window - basilar membrane

Answer 37

scala tympani

Question 38

separates the scala tympani from the cochlear duct

Answer 38

basilar membrane

Question 39

the apex where the scala vestibuli and scala tympani are continuous

Answer 39

helicotrema

Question 40

- located in cochlear duct - rests on the basilar membrane - contains hair cells which have stereocilia

Answer 40

spiral organ (organ of corti)

Question 41

when sound waves enter the scala vestibuli they vibrate a small portion of the basilar membrane

Answer 41

stereocilia

Question 42

responds to the highest frequencies (high notes)

Answer 42

basilar membrane closest to oval window

Question 43

responds to lower frequencies (low notes)

Answer 43

basilar membrane farthest from oval window

Question 44

this is touched by stereocilia when the basilar membrane moves

Answer 44

tectorial membrane

Question 45

causes a nerve impulse - nerve impulses are sent to the brain via the cochlear division of the vestibulocochlear nerve (CN VIII) - remaining sound waves are transferred to the scala tympani and exit the inner ear via the round window

Answer 45

sterocilia bends

Question 46

1. sound waves are collected by the auricle, travel in external acoustic meatus, sent to tympanic membrane 2. vibrations of tympanic membrane causes vibration of auditory ossicles, which in turn vibrate the oval window 3. sound waves travel through the scala vestibuli and vibrates a portion of the basilar membrane (which is attached to the spiral organ) 4. stereocilia of the hair cells bend against the tectorial membrane and a nerve impulse is generated 5. nerve impulse is sent to brain via the vestibulocochlear nerve (CN VIII)

Answer 46

process of hearing