Chapter 20 Ear

Question 1

Pinna (auricle)

Answer 1

functions to collect sound

Question 2

Primary parts of ear

Answer 2

helix (rim) & tragus

Question 3

Skin of auditory canal innervated by…

Answer 3

CN X

Question 4

In auditory canal?

Answer 4

• ceruminous glands
• sebaceous glands
• hairs

Question 5

Tympanic membrane

Answer 5

• ear drum

- 2 layers

Question 6

External auditory canal

Answer 6

cartilage + meatus (bone)

Question 7

TMD=

Answer 7

TMJ dysfunction (shared nerves)

Question 8

Middle ear

Answer 8

outer ear/ear drum + pharynx + mastoid sinus + inner ear

Question 9

Squamous portion

Answer 9

thin

Question 10

Petrosal portion

Answer 10

massive

Question 11

What is stretched across external auditory canal?

Answer 11

ear drum

Question 12

Auditory ossicles

Answer 12

malleus, incus, stapes

Question 13

What do the auditory ossicles do?

Answer 13

carry vibrations from ear drum > oval window

Question 14

Tensor tympani muscle attaches to…

Answer 14

malleus

Question 15

Stapedius muscle attaches to…

Answer 15

stapes

Question 16

Tympanic reflex

Answer 16

• tension on ear drum

- stapedius “locks-down” the ossicular chain= dampens loud sounds

Question 17

Auditory (eustachian) tube

Answer 17

• connects middle-ear to pharynx

- equalizes pressure across tympanic membrane

Question 18

Inflammation to the auditory tube

Answer 18

• infectious material trapped in middle ear
• fluid builds up and pressure
• threatens ear drum & hearing/balance

Question 19

Change in pressure =

Answer 19

change in altitude

Question 20

Myringotomy

Answer 20

• tubes that perforate the ear drum

- releases fluid from middle ear

Question 21

Labyrinthitis

Answer 21

infection of inner ear

Question 22

Embryo jaw muscle & nerve

Answer 22

tympani m. V3

Question 23

Adult jaw muscle & nerve

Answer 23

Masseter, etc V3

Question 24

Hyoid arch muscle & nerve

Answer 24

stapedius m. VII

Question 25

Osseous labyrinth

Answer 25

- -boney canals in petrous portion of the temporal bone | - membranous labyrinth is housed w/in the boney labyrinth

Question 26

Membranous labyrinth

Answer 26

-hollow tubes within osseous labyrinth

Question 27

Endolymph

Answer 27

fills each canal/chamber

Question 28

Perilymph

Answer 28

space btw oss. & memb. labyrinths

Question 29

Hair cell

Answer 29

- hearing & equilibrium - located throughout membranous labyrinth - vibration/movement of stereocilia = signal (VIII)

Question 30

Ampullae

Answer 30

- swelling at base of canal | - hair cells aligned in ridge = crista

Question 31

Cupula

Answer 31

- tips of hair cells embedded in gel | - distorted by endolymph movement = sensitive to changes in position

Question 32

Sound

Answer 32

vibration of air molecules

Question 33

High-pitched tones

Answer 33

- high frequency - short wave-lengths travel short distances - pin-drop

Question 34

Low-pitched tones

Answer 34

- low frequency - long wave-length travel long distances - truck

Question 35

Hearing ability

Answer 35

determined by body size

Question 36

Cochlea

Answer 36

Region of inner ear responsible for hearing

Question 37

Cochlear duct

Answer 37

- coiled tube resembling a snail's shell | - part of the membranous labyrinth

Question 38

Basal membrane

Answer 38

floor of cochlear duct

Question 39

Cochlear duct lies btw two other ducts

Answer 39

vestibular duct & tympanic duct

Question 40

Vestibular duct

Answer 40

- oval window to the helicotrema | - filled with perilymph

Question 41

Tympanic duct

Answer 41

- helicotrema to the round window | - filled with perilymph

Question 42

Helicotrema

Answer 42

- helical extremity | - tip of cochlea

Question 43

Oval window membrane

Answer 43

vestibular duct

Question 44

round window

Answer 44

tympanic duct

Question 45

Organ of Corti

Answer 45

- auditory receptor - tips of hair cells in contact with tectorial membranes - signal > cochlear part of CN VIII

Question 46

Sound transduction

Answer 46

1. sound vibrates the ear drum which vibrates ossicles 2. stapes oscillates within the oval window 3. membrane vibrates the perilymph in vestibular duct 4. vibrations go around helicotrema into tympanic duct 5. pressure causes round window to bulge outwards

Question 47

Perilymph in vest/tymp ducts...

Answer 47

distorts the basal membrane

Question 48

Problem with hair-cells

Answer 48

generic in size, shape, and function

Question 49

Place-theory

Answer 49

- sweet-spot along BM | - combination of wave-length/location= sound

Question 50

Basilar membrane is ribbon-like

Answer 50

- thick/stiff at the base | - thin/floppy @ helicotrema

Question 51

High pitch/short wavelengths/short distance

Answer 51

base of BM

Question 52

Low pitch/long wavelength/long distance

Answer 52

tip of BM