The Ear

Question 1

Which bone houses the vestibule-cochlear apparatus

Answer 1

The petrosal temporal bone

Question 2

Which two cranial nerves pass the internal aucostic meatus

Answer 2

The vestibulocochlaer and facial nerve

Question 3

What is the ear the organ of

Answer 3

Hearing and equilibrium

Question 4

What membrane separates the middle ear from the external ear

Answer 4

The tympanic membrane

Question 5

Which structure joins the nasopharynx to the middle ear

Answer 5

The auditory tube

Question 6

How does the external ear deal with the hearing process

Answer 6

The auricle and external aucostic meatus capture sound waves and direct them to the tympanic membrane

Question 7

How does the internal ear process hearing

Answer 7

The semi-circular canals and the cochlea convert mechanical signals to electric signals which are transmitted to the brain via the vestbulocochlear nerve

Question 8

What is the main sensory innervation of the external ear

Answer 8

Largely by the greater auricular and auriculotemporal nerves

Question 9

What is the function of the external ear

Answer 9

Supportive function
- catches and funnels the sound into the external aucoustic meatus and then to the tympanic membrane and inner ear

Question 10

What kind of epithelium is the external aucousti meatus lined with

Answer 10

Stratified squamous epithelium

Question 11

What are cermunious glands

Answer 11

The modified sweat glands that secrete ear wax

Question 12

What is the function of the ear wax and the hairs in the external aucostic meatus

Answer 12

To keep forgein bodes away from the tympanic membrane

Question 13

How is the tympanic membrane held in the temporal bone

Answer 13

By a fibrocatilganeous ring

Question 14

When looking in an otoscope of the tympanic membrane what is a key feature of a heathy ear and why is this?

Answer 14

A cone of light ( caused from light from the otoscope) this is health as it means there is no fluid accumulation or pathology

Question 15

Which are the two small muslces oresent in the tympanic cavity ( middle ear)

Answer 15

The stapedius and the tensor tympani

Question 16

What are the three ossicles of the ear

Answer 16

Malleus, incus and stapes

Question 17

What is the function of he tensor tympani and the stapedius

Answer 17

They resit the movement of the ossicles protecting hte ear if there are loud sounds

Question 18

What is the innervation to the stapedius

Answer 18

Nerve to stapedius - brach of the facial nerve

Question 19

What is the nerve supply of the tensor tympani

Answer 19

Mandibular divsion of the trigeminal nerve

Question 20

What does the end of the cartilagenouss tube of the auditory tube form

Answer 20

The torus tabuarius - in the wal of the nasopharynx

Question 21

What is the function of the auditory tube

Answer 21

To connect the middle ear with the nasopharynx and to facialte pressure equalisation

Question 22

Why can respiratory tract infections sometimes cause middle ear infections as well?

Answer 22

Due to the connection of the middle ear and the nasopharynx from the auditory tube which can often facialte infection spread

Question 23

Patient has a Schwannoma( begnign tumour affecting CN8) requiring surgery at the internal aucostic meatus - which nerve is potentially at risk

Answer 23

The facial nerve

Question 24

The facial nerve through its course gives off the greater petrosal nerve and chorda tympani - what are the functions of these nerves

Answer 24

Greater petrosal nerve sends parasympathetic fibres to the ptergopaltine ganglion

Chorda tympani - carrying parasympathetic fibres to submandibular ganglion and running with the lingual nerve. Taste to anterior 2/3 of the tongue

Question 25

The facial nerve also sends off a small branch called the nerve to stapedius what does this do

Answer 25

This nerve functions to innervate the stapedius muscle which dampens the movement of Stapes which is an ossicle

Question 26

Why is there a risk of infection between the middle ear and middle cranial fossa?

Answer 26

This is because the here is a thin roof of bone between these two areas, if the infection is very severe it can erode the bone and affect the vascular structures

Question 27

Which ossicle does the tensor tympani attach to

Answer 27

Malleus

Question 28

How re the mastoid air cells connected to the middle ear

Answer 28

Through mastoid antrum

Question 29

Infections in the middle ear are common and what re they most often caused by

Answer 29

Obstruction in the auditory tube

Question 30

Chronic ear infections may lead to the mastoid air cells causing a conditin called mastoiditis - why may surgeons be war of operating

Answer 30

Due to the close proximity of the facial nerve

Question 31

What is the medical name for chronic ear infections

Answer 31

Otitis media

Question 32

What does conductive hearing loss mean

Answer 32

When the issue is which transmission of sound mechanically via the ossicles rather than with the vestibulocochlear nerve

Question 33

What is glue ear

Answer 33

Otitis media with effusion - tends to affect children more and it is a build up of fluid in the ear behind the tympanic membrane - affecting hearing

Question 34

What organ does the inner ear contain

Answer 34

The vestubulocochealr organ which is concerned with reception of sound and maintenance of balance

Question 35

What kind of fluid does the only labyrinth in the inner ear contain

Answer 35

Perilypmh

Question 36

CN8 leaves the crnial fossae via the interal acoustic meatus and divides into two parts , what are these towparts and what are they responsible for

Answer 36

A cochlear nerve and a vestibular nerve Vestibular nerve = equilibrium and balance Cochlear =hearing

Question 37

What is neural hearing loss

Answer 37

This is when the problem is with the nerve or a problem with the cochlea Rather than the mechanical transmission of sound

Question 38

Where does the information the vestibular nerve carries come from

Answer 38

The semicircular canals

Question 39

Wha are some symptoms of damage to this nerve

Answer 39

Ataxia (clumsy voluntary movements) Vertigo ( feels like everything is spinning enough to affect balance ) Nausea This is because this nerve is responsible for balance o