Structures and functions of the ear

Question 1

3 divisions of the ear

Answer 1

External Ear
Middle ear
internal ear

Question 2

Which parts of the ear are responsible for hearing only, and which is responsible for hearing and balance?

Answer 2

External & middle ear - hearing only

Internal ear - hearing, and balance

Question 3

What is the Auricle and what is its function?

Answer 3

The fleshy part of the external ear on the outside of your head.

Its shape collects sounds waves and directs them to the external auditory canal

Question 4

Cerminious glands

Answer 4

The external ear is lined with these glands that produce cerumen, or ear wax

Question 5

What is the purpose of cerumen?

Answer 5

It prevents foreign objects from entering the ear

Question 6

What is the Tympanic Membrane and what is its function?

Answer 6

It separates the external ear from the middle ear and vibrates when sound waves reach it

It can be ruptured with an airplane change in altitude or when diving and can result in hearing impairment

Question 7

Where are mastoid air cells located

Answer 7

The middle ear, part of the one passage from the middle ear

Question 8

What is the auditory tube and what is its function

Answer 8

The other passage is from the middle ear. It equalizes air pressure between the middle and external ear cavity

Question 9

3 auditory ossicles of the inner ear and their function

Answer 9

Malleus
Incus
Stapes

They form a physical bridge to transmit vibrations from the tympanic membrane to the oval window

Question 10

What are the two muscles in the middle ear and what do they do?

Answer 10

The stapedius adn tensor tympani; they act as a reflex and dampen sounds that are too loud.

Question 11

Oval window

Answer 11

A hole in the bony membrane that receives sound waves from the three auditory ossicles

Question 12

The bony labyrinth

Answer 12

part of the inner ear with tunnels and channels inside the temporal bone

Question 13

membranous labyrinth

Answer 13

a smaller set of tunnels inside the bony labyrinth

Question 14

What are the 2 fluids in the inner ear, and what do they fill?

Answer 14

Endolymph - fills the membrainous labyrinth

Perilymph - fill sthe space between the membranous labrynth and bony labyringth

Question 15

What are the three regions of the bony labyrinth, and which are responsible for balance v hearing?

Answer 15

Vestibule > balance
Semicircular canal > balance
Cochlea > Hearing

Question 16

What are the three regions of the cochlea, and what fluid is each filled with?

Answer 16

Scala tympani > filled with perilymph
Scala vestibuli > filled with perilymph
Cochlear duct > filled with endolymph and contains the spiral organ

Question 17

Spiral organ

Answer 17

Is made of inner and outer hair cells (sensory cells of hearing) that attach to tectorial membrane.

Question 18

Cochlear ganglion

Answer 18

Groups of cell bodies that join to form the cochlear nerve, which then forms the vestibulocochlear nerve VIII

Question 19

Can sound pass through a vacuum?

Answer 19

No, sound must pass through matter

Question 20

Volume

Answer 20

Loudness - a function of amplitude

Question 21

Pitch

Answer 21

Sound wave frequency

Question 22

Timbre

Answer 22

resonance quality of a sound (why different instruments have different sounds)

Question 23

How does sound work?

Answer 23

1) External air collects sound waves >
2) sends them to the tympanic membrane >
3) tympanic membrane cuasees 3 auditory ossicle (malleus, incus, stapes) to vibrate >
4) cause the perilumph and endolymph to vibrate >
5) causes a distortion of basilar membrane
6) Basilar membrane causes bending of stereocilia in inner hair cells in the spiral organ

Question 24

What is the purpose of the round window

Answer 24

Protects the inner ear from pressure build up & dissipates sound waves

Question 25

What is the chemical reaction of hearing?

Answer 25

1) The inner hair cells pull on tip links, openin gup k+ channels
2) Then calcium ions enter and further depolarize the ion
3) depolarization releases glutamate, stimulating action potentials in the vestibulocochlear nerve

Question 26

Endocochlear potential

Answer 26

The K+ charge difference between the endolymph and perilymph

Question 27

What is the neuronal path of hearing?

Answer 27

Vesibulocochlear nerve > 
Medulla oblongata >
Inferior colliculi >
Thalamus >
Auditory cortex

Question 28

Presbyacusis

Answer 28

Decrease in hair cells in cochlea causing age-related hearing loss

Question 29

Conductive hearing loss

Answer 29

Problem with the transmission of sound waves from the external ear to the spiral organ.

Can remove the blockage or use hearing aids.

Question 30

Sensorineural hearing loss

Answer 30

Spiral organ or neuronal pathways are damaged. Can use hearing aids

Question 31

2 parts of the balance organ and their functions

Answer 31

static labyrinth > evaluated position relative to gravity

dynamic labyrinth > evaluates the movement of the heads

Question 32

2 parts of the static labyrinth

Answer 32

Utricle

Succule

Question 33

what are the names of the specialized epithelium in the utricle and succule

Answer 33

utricular macula
saccular macula

They resemble spiral organ

Question 34

Otolith membranes

Answer 34

Respond to gravity by bending

Question 35

What is the position of the 3 semicircular canals of the dynamic labyrinth

Answer 35

X Y Z axis

Question 36

Ampilla

Answer 36

The base of semicircular canals

Question 37

Crista ampularis

Answer 37

The specialized epithelium that lines the ampilla

Question 38

Cupola

Answer 38

A gelatinous mass with hair cells embedded - a “float” -associated the ridge of the crista amuplaris that is displaced by movements

Question 39

Neuronal pathway of balance

Answer 39

1) Neurons on macuale and crista >
2) converge to vestibular ganglion >
3) Join vestibulcochlear nerve >
4) Medulla oblongata >
5) CNS, Spinal cord