Exam 3 ear

Question 1

Hearing (audition) definition

Answer 1

detecting sound waves and converting them into nerve impulses

Question 2

What are the components of the external ear

Answer 2

auricle
External auditory meatus
Tympanic membrane (eardrum)

Question 3

What are the components of the middle ear

Answer 3

auditory tube
Auditory ossicles 
-malleus
-incus
-stapes

Question 4

What are the components of the inner ear

Answer 4

bony labyrinth

Membranous labyrinth

Question 5

What is the auricle and its function

Answer 5

outer mass of tissue

Function: Collect sound waves and direct them into auditory canal

Question 6

What is the External auditory meatus and its function

Answer 6

between auricle and tympanic membrane

Function: Directs sound waves to tympanic membrane (eardrum)

Question 7

What is the function of the tympanic membrane

Answer 7

move/vibrate auditory ossicles when sounds vibrate the tympanic membrane
-sound waves into physical vibrations

Question 8

What are the auditory ossicles and their function

Answer 8

ear bones: 
- malleus 
- incus
- stapes
Function: Transmit and amplify vibrations from the eardrum to inner ear

Question 9

what is the auditory (eustachian) tube and its function

Answer 9

connects middle ear with the nasopharynx

function: equalizes air pressure in the middle ear

Question 10

what is ottis media

Answer 10

middle ear infection

• fills up with fluid/ puss
• eardrum bulges outward
• infection can travel via the auditory tube

Question 11

what is the bony labyrinth

Answer 11

spaces/cavities inside temporal bone

Question 12

what is membranous labyrinth

Answer 12

membranous sacs/tubes that rest inside the bony labyrinth

Question 13

what is perilymph

Answer 13

fluid in between bony and membranous labyrinths

• inside bony part and outside membranous
• make it “float”
• chemically similar to CSF

Question 14

what is endolymph

Answer 14

fluid inside membranous labyrinth

• low sodium and high potassium conc
• helps conduct sound vibrations and detect changes in position/balance

Question 15

describe the structure of the bony labyrinth components:
vestibule
semicircular canals
cochlea

Answer 15

vestibule: oval central portion
semicircular canals: 3 circular spaces/canals
cochlea: spiral chamber

Question 16

describe the structure of the membranous labyrinth components:
utricle
saccule
semicircular ducts
cochlear duct (scala media)

Answer 16

utricle: sac inside vestibule
saccule: another sac inside vestibule
semicircular ducts: 3 membranous tubes in semicircular canals
cochlear duct: membranous tube inside cochlea

Question 17

what is the scala vestibuli

Answer 17

above cochlear duct

• connects to oval window
• filled with perilymph
• continuous with apex

Question 18

what is the vestibular membrane

Answer 18

thin membrane that separates the scala vestibuli from the cochlear duct

Question 19

what is the scala tympani

Answer 19

below cochlear duct

• connects to round window
• filled with perilymph
• continuous with apex

Question 20

what is the basilar membrane

Answer 20

separates scala tympani from cochlear duct

Question 21

which structure responds to the highest sound frequencies

Answer 21

basilar membrane, closest to the oval window

Question 22

which structure responds to the lower sound frequencies

Answer 22

basilar membrane, furthest away from the oval window

Question 23

what happens when sound waves enter the scala vestibuli

Answer 23

vibrate a small portion of the basilar membrane

Question 24

explain the process of hearing

Answer 24

• sound waves are collected by auricle, travel to external acoustic meatus, then tympanic membrane
• vibrations travel from tympanic membrane, to auditory ossicles, to oval window
• sound waves travel through the scala vestibuli and vibrate basilar membrane
• stereocilia bend against tectorial membrane, nerve impulse generated
• CN VIII takes impulse to brain
• remaining impulses leave through round window