Aud. & Hearing Impairment

Question 1

Anatomy of the auditory system includes what structures?

Answer 1

Structures of the outer ear, middle ear and inner ear (p. 410)

Question 2

Cartilage framed appendage covered w/ skin that appears around the 6th weak of gestation from 1st and 2nd branchial arches.

Answer 2

The Pinna (Auricle) (p. 410)

Question 3

What are the 6 major structures of the pinna?

Answer 3

1. Helix
2. Antihelix
3. Concha
4. Tragus
5. Antitragus
6. Lobe ( p. 410)
   (look at picture :)

Question 4

Which nerve innervates the pinna?

Answer 4

trigeminal nerve (CN V)
sensory innervation
(p. 410)

Question 5

The external auditory meatus (EAM) is an s-shaped oval canal ___ to ___ mm in length. It opens at the ______ and terminates at the _____________.

Answer 5

25 to 33 mm
pinna
tympanic membrane
(p. 410)

Question 6

The EAM is innervated by which CNs?

Answer 6

CNs trigeminal (V), facial (VII), vagus (X).
(p. 410)

Question 7

The tympanic membrane does what?

Answer 7

It transduces sound (p. 410)

Question 8

What is the function of the outer ear?

Answer 8

It serves an auditory function in which the OE collects sounds and channels it to the middle ear. (p.410)

Question 9

The OE serves as a natural filter and enhances or boosts higher frequency sounds by how many dB?

Answer 9

10 to 12 dB (p.411)

Question 10

What is the natural resonance of the concha?

Answer 10

5000 Hz (p. 411)

Question 11

Besides auditory function, what other function does the OE serve?

Answer 11

protection

• cerumen ‘noxious’ to introders
• s-shape prevents foreign objects from reaching ME and TM (p. 411)

Question 12

A six walled air filled cavity within the petrous portion of the temporal bone.

Answer 12

the middle ear (p.411)

Question 13

The middle ear houses what?

Answer 13

3 ossicles (bones)  
5 ligaments
2 muscles (tendons) (p.411)

Question 14

What does the ossicular chain consist of & what does it do?

Answer 14

3 bones (smallest in human body) 
transfers the mechanical vibrations from TM to inner ear 
(p. 411)

Question 15

______= the most lateral ossicle, consisting of manubrium, head, neck and lateral and anterior processes; attached to the TM and the incus.

Answer 15

Malleus (p. 411)

Question 16

______ = the middle and largest bone in the ossicular chain consisting of a body and a short, long, and lenticular process.

Answer 16

Incus (p. 411)

Question 17

______= the most medial third and smallest ossicle consisting of a head, footplate, and 2 crura. The footplate is held in the oval window by annular ligament.

Answer 17

Stapes (p. 411)

Question 18

What are the 5 ligaments that suspend the ossicular chain in the ME?

Answer 18

1. superior malleolar
2. lateral malleolar
3. anterior malleolar
4. posterior includal
5. annular ligament
   (p. 411)

Question 19

What function do the 2 muscles in the ME serve?

Answer 19

Hold ossicular chain in place and reduce intensity reaching IE by pulling against each other to stiffen system and reducing efficiency of ME. (p. 411)

Question 20

What are the 2 muscles in the ME?

Answer 20

The tensor tympani and the stapedius muscle (p. 411)

Question 21

Tensor tympani pulls malleus ______.

Answer 21

medially (p. 411)

Question 22

Stapedius muscle (smallest muscle in body) pulls stapes _____ and tilts what?

Answer 22

Pulls stapes posteriorly and tilts footplate in oval window (p. 411)

Question 23

_________= mucosal lined pathway that ventilates the ME through the connection to the nasopharynx.

Answer 23

Eustachian tube (p. 411)

Question 24

impedance mismatch = ?

Answer 24

loss of sound energy (p. 411)

Question 25

How does the ME compensate for impedance mismatch? How much is compensated?

Answer 25

two primary mechanisms --> lever effect & ME muscles increase sensitivity 25 to 27 dB of estimated 30dB is compensated (p. 411)

Question 26

Complex structure residing within the petrous portion of the temporal bone

Answer 26

Inner ear (p. 411)

Question 27

What are the 2 functions of the IE?

Answer 27

sense of hearing (cochlea) and sense of balance (semicircular canals and otolithic organs) (p. 411)

Question 28

semicircular canals: ________ movement :: utricle/saccule : _________ movement

Answer 28

angular linear (p. 412)

Question 29

a bony canal that surrounds a membranous tube, about 35 mm in length & coils around central core approx 2 3/4 turns.

Answer 29

cochlea (p. 412)

Question 30

base of cochlea : ____ :: vestibule: ______

Answer 30

largest turn smallest turn (p. 412)

Question 31

________= upper canal running from oval window to helicotrema; contains perilymph

Answer 31

scala vestibuli (p. 412)

Question 32

_______= lower canal running from the round window to helicotrema; contains perilymph

Answer 32

scala tympani (p. 412)

Question 33

______= middle canal divided from scala vestibuli by Reissner's membrane and from scala tympani by basilar membrane; contains organ of corti & contains endolymph.

Answer 33

scala media (p. 412)

Question 34

The organ of corti consists of ?

Answer 34

sensory hair cells, support cells and support membranes and ligaments (p. 412)

Question 35

How many (sensory) Outer Hair Cells (OHC) are there approx?

Answer 35

13,500 per ear; housed in 3 to 4 rows (p. 412)

Question 36

The OHC serve as?

Answer 36

biologic modifier increasing or decreasing sensitivity to sounds by changing length of hair cells ( p. 412)

Question 37

How many (sensory) Inner Hair Cells (IHC) are there approx?

Answer 37

3500 per ear housed in 1 row (p. 412)

Question 38

The IHC serve as?

Answer 38

serve to process frequency, temporal and intensity info to auditory pathway (p. 413)

Question 39

The basilar membrane yields what?

Answer 39

Tonotopicity in which high frequencies are processed at the base and low frequencies at the apex (p. 413)

Question 40

What is the tectorial membrane responsible for?

Answer 40

For shearing the stereocilia of the hair cells (p. 413)

Question 41

What is the main function of the IE?

Answer 41

Changes the mechanical energy into hyrdomechanical energy and then into neural impulses (p. 413)