Chapter 15 -- Hearing and Balance

Question 1

What are the three main areas of the ear?

Answer 1

External ear: (hearing). Terminates at eardrum
(tympanic membrane). Includes auricle and external auditory meatus

Middle ear: (hearing). Air-filled space containing auditory ossicles

Inner ear: (hearing and balance). Interconnecting fluid-filled tunnels and chambers within the temporal bone

Question 2

What is the name of the visible protruding part of the ear?

Answer 2

Auricle or Pinna

Question 3

What is the name of the visible tunnel of our ear?

Answer 3

External Auditory Meatus

Question 4

What is the name of the membrane of the external ear that vibrates during sound? Describe it.

Answer 4

Tympanic membrane

Sound waves cause it to vibrate

Border between external and middle ear

Question 5

What are the names of the three bones found in the middle ear?

Answer 5

Auditory Ossicles: Malleus, incus, stapes

Question 6

What is the border between the middle ear and the inner ear?

Answer 6

The oval window, the foot of stapes rests here.

Question 7

What is the name of the tube that opens into the pharynx?

Answer 7

Eustachian Tube or Auditory Tube

Question 8

What are the two labrynths of the inner ear?

Answer 8

Bony Labrynth: chambers in the temporal bone

Membranous: tunnels and chambers in the bony labyrinth

Question 9

Name the three areas of the ear where we find bondy labyrinth.

Answer 9

Cochlea: hearing
Vestibule: balance
Semicircular canals: balance

Question 10

What are the two types of lymph or liquid found in the ear?

Answer 10

Endolymph: in membranous labyrinth
Perilymph: space between membranous labyrinth and periosteum of bony labyrinth

Question 11

What are the two chambers of the cochlea that are filled with perilymph?

Answer 11

scala vestibuli

scala tympani

Question 12

What type of membrane lines the wall of the scala vestibuli?

Answer 12

vestibular membrane

Question 13

What type of membrane lines the wall of the scala tympani?

Answer 13

basilar membrane

Question 14

What is the name of the duct between the scala vestibuli and scala tympani?

Answer 14

Cochlear duct (scala media). Filled with endolymph

Question 15

Describe the cells found in the cochlear duct

Answer 15

Spiral organ (organ of Corti) are the cells found in the cochlear duct.

Contains:
Supporting epithelial cells and specialized hair cells with stereocilia hair-like projections

Question 16

What is the function of stereocilia?

Answer 16

They transfer information from one stereocilia to another by use of the tip links mechanically gated ion channel.

Tip link (gating spring) attaches tip of each stereocilium in a hair bundle to the side of the next longer stereocilium.

Question 17

Describe two of the qualities of sound

Answer 17

Volume or amplitude: function of wave amplitude

Pitch: function of wave frequency

Question 18

Describe how sound travels through your ear.

Answer 18

1. Sound waves strike the tympanic membrane and cause it to vibrate.
2. Sound waves strike the tympanic membrane and cause it to vibrate.
3. The foot plate of the stapes vibrates in the oval window.
4. The vibrations of the oval window causes a vibration through the cochlea and vibrates the perilymph.

Question 19

What are the two muscles of the middle ear that move the ossicles?

Answer 19

Tensor tympani: inserts on malleus

Stapedius: inserts on stapes