Structure of the ear

Question 1

Explain the process of hearing

Answer 1

Hearing is the process by
which the ear transforms
sound vibrations in the
external environment into
nerve impulses that are
conveyed to the brain, where
they are interpreted as sounds

Question 2

What are the 3 main structures of the ear

Answer 2

The outer ear
The middle ear
The inner ear

Question 3

What are the structures are in the outer ear

Answer 3

The Pinna and the Ear Drum

Question 4

What does the Pinna do

Answer 4

It is the part of your ear that you can see, it collects sound waves and channels them into the auditory canal this passes through the canal to meet the ear drum

Question 5

What does the Ear Drum do

Answer 5

It is a transparent membrane which is sensitive to the vibrations of the ear - as the air vibrates so does the ear drum
It also separates the outer ear from the middle ear

Question 6

What are the structures of the Middle ear

Answer 6

The ossicles - which consists of the mallus, incus and stapes

Question 7

Explain how sound transfers in the middle ear

Answer 7

As the ear drum vibrates so does the ossicles which transfers vibrations from the ear drum into the inner ear

Question 8

What are the main functions of the ossicles

Answer 8

To increase or amplify pressure of sound waves when it reaches the inner ear

Question 9

What are the structures of the inner ear

Answer 9

The Cochlea
The organ of Corti
The Basilar Membrane

Question 10

What are the main functions of the Cochlea

Answer 10

Nothing gets heard until the vibrations are converted into electricity and send to the brain - this is what the cochlea does

The Cochlea contains a liquid that vibrates. The cells in the cochlea convert these vibrations into electrical signals. The electrical signals go through the auditory nerves to the brain. The electrical signals are sensitive to loudness and frequency

Question 11

What is the Organ of Corti

Answer 11

This is in the inner ear within the Cochlea. It includes 3 rows of outer hair cells and one row of inner hair cells.

The Outer hair cells: 3 rows
- contact with the tectorial membrane
(stereocillia move when tectorial membrane
moves)
- amplify low level sounds
- respond to certain frequencies

The inner hair cells: 1 row
-convert the sound from vibrations of the
fluid to electrical signal
-Signal then transmitted to the brain via the
auditory nerve (cochlear nerve)

Question 12

Explain the process of hearing:

Answer 12

1) The Pinna catches sound
2) Sound is funnelled into the auditory canal
3) Sound is amplified in the auditory canal
4) Sound is funnelled towards the tympanic membrane
5) Tympanic membrane vibrates as air hits it
6) Tympanic membrane vibrates ossicles
7) Ossicles then amplify the sound and vibrate the oval window
8) Fluid then vibrates in the inner ear and the basilar membrane vibrates
9) Hair cells in the organ of corti vibrate
10) Hair cells then convert vibrations to electrical signals
11) Electrical signals are then transmitted to the brain via the auditory nerve and vestibulococlear nerve
12) Information is processed via the primary auditory cortex in the temporal lobe

Question 13

What do the inner and outer hair cells do

Answer 13

The Outer hair cells: 3 rows
- contact with the tectorial membrane
(stereocillia move when tectorial membrane
moves)
- amplify low level sounds
- respond to certain frequencies

The inner hair cells: 1 row
-convert the sound from vibrations of the
fluid to electrical signal
-Signal then transmitted to the brain via the
auditory nerve (cochlear nerve)

Question 14

What are the types of hearing loss

Answer 14

Conductive and Sensorineural and also Mixed hearing loss

Question 15

Which parts of the ear does conductive hearing loss affect

Answer 15

The outer and middle ear

Question 16

Which parts of the ear does sensorineural hearing loss affect

Answer 16

The inner ear

Question 17

Explain Conductive Hearing Loss

Answer 17

Conductive hearing loss happens when there is an issue transferring the sound waves

Question 18

What are some of the outer ear causes of conductive hearing loss

Answer 18

Blockage of ear e.g. wax or bug
Infection e.g. swimmers ear or infection due to use of cotton bud
Auditory canal tumour
Abnormal bone growth in ear canal - linked to cold water swimming

Question 19

What are some of the middle ear causes of conductive hearing loss

Answer 19

Perforated or scarring of the ear drum

or

Otitis Media (Glue Ear) - Eustachian tube blocked then allows fluid from the nasal cavity to enter the middle ear and does not allow the fluid to drain - can contribute to the delay in development of speech and language skills

Question 20

What is sensorinural hearing loss

Answer 20

The ear works but the messages to the brain do not get processed

Question 21

What are some of the causes of sensorinural hearing loss

Answer 21

Congenital - stroke- damage to the cochlea
and/or auditory cortex in brain (head injury –
acquired)
Viral infections e.g Congenital rubella
syndrome (CRS) – maternal transmission of
rubella virus, Cytomegalovirus (CMV) infection
Disease – Inflammation Suppurative labyrinthitis
or otitis interna (inflammation of the inner ear)
Noise induced - cause of approximately half of
all cases of hearing loss, causing some degree
of problems in 5% of the population globally

Question 22

Explain how hearing can be damaged by bacterial meningitis

Answer 22

Bacteria that our bodies produce to fight infection may get into the inner ear where they can cause damage to the hair cells of the cochlea or nerve fibres. This is a sensorineural hearing loss and permanent

Question 23

What type of hearing loss is bacterial meningitis

Answer 23

sensorineural hearing loss

Question 24

How can Otitis Media affect hearing

Answer 24

Otitis Media (Glue Ear) - Eustachian tube blocked then allows fluid from the nasal cavity to enter the middle ear and does not allow the fluid to drain - can contribute to the delay in development of speech and language skills