anatomy

Question 1

outer ear is made up of 2 structures:

Answer 1

1. pinna

2. external auditory meatus (ear canal)

Question 2

concha

Answer 2

depression in lower center of the pinna

Question 3

funnel like shape of the pinna gives rise to its basic function of…

Answer 3

collecting and sending sound waves through the ear canal

Question 4

external auditory meatus (EAM)

Answer 4

• tube that runs from the pinna to the ear drum (tympanic membrane)
• lined with epithelium and tiny hairs (cilia)
• contains glands in the cartilaginous parts that produce earwax

Question 5

EAM length

Answer 5

children = 6mm
adults = 23-29mm

Question 6

function of cerumen

Answer 6

-aids in keeping the ear canal moisturized and clean of debris that can accumulate

Question 7

2 main functions of EAM

Answer 7

• protect the delicate middle and inner ear from foreign bodies that could damage these structures
• boosts amplitude of high frequency sounds

Question 8

resonant frequency

Answer 8

or natural frequency

the frequency in which so meting responds or vibrates best to

Question 9

when frequencies enter the EAM and are close to or at the resonant frequency of the EAM what happens?

Answer 9

they get an automatic boost of about 10-15 dB

Question 10

the boost helps

Answer 10

higher frequency sounds

localization

Question 11

tympanic membrane

Answer 11

anatomic boundary between outer and middle ear

Question 12

TM is comprise of multiple layers:

Answer 12

epithelial, medial membranous, fibrous (in-between top 2)

Question 13

TM medial layer

Answer 13

lined with mucous membrane

Question 14

TM 2 main sections

Answer 14

• pars flaccida

- pars tens

Question 15

pars flaccida

Answer 15

located superiorly

is flaccid

Question 16

pars tens

Answer 16

larger section

more stiff

located inferiorly

Question 17

ossicles

Answer 17

smallest bones in the body

• malleus
• incus
• stapes

all articulate with each other
suspended by ligaments that help it move

Question 18

malleus

Answer 18

attaches with the TM

-TM vibrates from sound energy impinging on it and malleus moves at the same vibratory speed

Question 19

incus

Answer 19

middle bone, less than 1cm

Question 20

2 processes of incus

Answer 20

short crus

long crus

Question 21

long crus

Answer 21

attached to head of stapes

Question 22

short crus

Answer 22

fits into recess wall of TM

Question 23

stapes

Answer 23

resembles stirrup

has 2 crura and a footplate

Question 24

footplate function

Answer 24

helps push acoustic energy into the inner ear

fits into oval window

Question 25

E- tube functions

Answer 25

• equalize air pressure between middle ear cavity and the nasopharynx
• help drain fluids that may accumulate in the middle ear

Question 26

inner ear consists of

Answer 26

the auditory and vestibular labyrinth

-each has a osseous and membranous labyrinth

Question 27

cochlea

Answer 27

snail shape part of osseous labyrinth

• HOUSED WITHIN THE TEMPORAL BONE
• straightened out is about 3.5 cm
• tonotopially organized

Question 28

membranous labyrinth

Answer 28

goes inside osseous lab

Question 29

auditory lab is referred to as the

Answer 29

cochlea and is the sensory organ of hearing

Question 30

semicircular canals

Answer 30

sensory end organ of balance

Question 31

cochlea tonotopical organization

Answer 31

• different parts respond to different frequencies
• lined with hair cells
• higher freqs on the outside, abused the most, go first

Question 32

3 scalas

Answer 32

scala vestibuli (perilymph)
scala media (endolymph)
scala tympani

Question 33

basilar membrane location

Answer 33

base of cochlea

Question 34

vestibular membrane location

Answer 34

roof of cochlea

Question 35

cilial hair fibers

Answer 35

attached to nerve fibers

Question 36

techtorial membrane

Answer 36

shearing forces activates cilia movements

Question 37

stereocilia

Answer 37

highest hair cells