Anatomy of the Auditory System

Question 1

Outer ear

Answer 1

Pinna
External auditory canal

Question 2

Pinna

Answer 2

Cartilage covered with skin
Conducts sound to the middle ear
Aids in localization and sound collection

Question 3

External auditory canal

Answer 3

First third is cartilaginous, second third is osseous
Conducts sound to the tympanic membrane
Protects TM from trauma
Sebaceous glands secrete cerumen

Question 4

Middle ear

Answer 4

Tympanic membrane
Ossicles
Eustachian tube
Muscles

Question 5

Tympanic membrane

Answer 5

Concave disklike structure
3 layers
Cone of light
Converts acoustic energy into mechanical energy

Question 6

Ossicles

Answer 6

Malleus, incus, stapes
Malleus connects to TM
Stapes connects to oval window
Conducts sound from TM to inner ear

Question 7

Eustachian tube

Answer 7

Tube in the posterior-inferior portion of the ME space
Leads to nasopharynx
Maintains equal pressure between the ME and atmosphere
Opens periodically through jaw movement

Question 8

Middle ear muscles

Answer 8

Stapedius
Tensor Tympani

Question 9

Stapedius

Answer 9

Attaches to the neck of the stapes
Contract to loud sounds

Question 10

Tensor tympani

Answer 10

Attaches to the manubrium of the malleus
Contracts in response to non-auditory stimulation

Question 11

Inner ear

Answer 11

Oval window
Vestibule
Round window
Cochlea

Question 12

Oval window

Answer 12

Separates the inner ear from the middle ear

Question 13

Vestibule

Answer 13

The immediate entryway into the inner ear

Question 14

Round window

Answer 14

Opening that vibrates opposite in phase from vibrations entering the cochlea via the oval window

Question 15

Cochlea

Answer 15

A snail-shaped, fluid-filled space with 2.5 turns, 35 mm in length
3 fluid filled chambers: scala vestiboli, scala tympani, scala media

Question 16

Basilar membrane

Answer 16

Membrane in the cochlea that the basilar membrane sits on

Question 17

Tonotopic organization

Answer 17

Auditory nerve fibers response are frequency specific
Base of cochlea responds to high frequencies
Mid to apex of cochlea responds to low frequency sounds

Question 18

Scala media

Answer 18

Lies between the Scala vestibule and tympani, sectioned by 2 membranes
Organ of corti

Question 19

Organ of corti

Answer 19

Sits on basilar membrane
Contains the sensory cells of hearing

Question 20

Tectorial membrane

Answer 20

Covers the organ of corti
Tips of the outer hair cell stereo cilia are embedded in it

Question 21

Inner hair cells vs outer hair cells

Answer 21

Inner hair cells have 1 row, 3,000 total
Outer hair cells have 3 parallel rows, 12,000-15,000 total

Question 22

Motion of fluid within the utricle and saccule

Answer 22

Linear acceleration
Ex: elevator moving, car changing speed

Question 23

Motion of fluid in the semicircular canals

Answer 23

Angular acceleration
Ex: changes in head/body position

Question 24

Basic pathway of hearing

Answer 24

Enter ear, sound/vibration from middle ear, traveling wave in cochlear partition, basilar membrane moves, hair cells shear, cilia of hair cells bend, chemical/mechanical release, action potential of auditory nerve

Question 25

Final destination for speech information processing

Answer 25

Temporal lobes

Question 26

Outer ear disorders (pinna)

Answer 26

Microtia Anotia Cauliflower ear Malignant tumors Atresia

Question 27

Outer ear disorders (ear canal)

Answer 27

Collapsing ear canal Foreign bodies External otitis Necrotizing/malignant external otitis Growths Cerumen Injuries

Question 28

Middle ear disorders

Answer 28

Perforations of the TM Otitis media Cholesteatoma Otosclerosis Ossicular chain discontinuity Eustachian tube dysfunction Barotrauma