Wk 11 - The ear

Question 1

What are the 3 general components of the ear?

Answer 1

External ear Middle ear Inner ear

Question 2

What makes up the external ear?

Answer 2

Auricle External acoustic meatus (so down to the tympanic membrane)

Question 3

What epithelium lines the external acoustic meatus?

Answer 3

Skin Have hairs and cerumen glands

Question 4

What are cerumen glands ?

Answer 4

The glands producing ear wax

Question 5

What makes up the middle ear?

Answer 5

-tympanic cavity -3 ossicles -auditory tube -tympanic membrane

Question 6

What is the middle ear filled with?

Answer 6

Air

Question 7

What are the components of the internal ear?

Answer 7

• Cochlea
• Semicircular canals

Question 8

What is the cochlea concerned with?

Answer 8

Hearing

Question 9

What are the semilunar canals concerned with?

Answer 9

The position of head in space Also allows you to move your head while keeping eyes fixed on something

Question 10

What are the 3 ossicles and what kind of joints are found between them?

Answer 10

-Stapes -Malleus -Incus Synovial joints

Question 11

What is the most common cause of deafness?

Answer 11

Build-up of wax

Question 12

What nerve supplies the inner ear?

Answer 12

Vestibulocochlear - supplies the vestibule and cochlea

Question 13

What ossicle attaches to the tympanic membrane and where?

Answer 13

The handle of the malleus at the most concave part called the umbo

Question 14

When does the auditory tube open up? (what action makes this happen?)

Answer 14

When you yawn

Question 15

What condition can affect the synovial joints of the ossicles?

Answer 15

Arthritis - can make it harder to hear

Question 16

Where does the stapes sit? What holds it in place?

Answer 16

the footplate sits in the oval window

Stapedius muscle

Question 17

What two muscles are part of the reflex which protects the ear from loud noises?

Answer 17

Stapedius muscle

Tensor tympani

Question 18

Describe the action of the stapedius muscle.

Answer 18

If there is a loud sound it is part of a reflex and it will contract and pull on the stapes to restrict its movement so it doesn’t move out and in too much

Question 19

Describe the action of the tensor tympani.

Answer 19

It is attached to the handle of the malleus.

When there is a loud sound it contracts and pulls on the tympanic membrane to restrict movement/vibration and therefore sound

Question 20

What nerve is the tensor tympani supplied by and it is formed from what pharyngeal arch?

Answer 20

CN5 - first pharyngeal arch

Question 21

What nerve is the stapedius muscle supplied by and what pharngeal arch is it formed from?

Answer 21

CN7 - 2nd pharyngeal arch

Question 22

Describe how sound is turned into an electrical impulse to be recieved in the brain.

Answer 22

When we hear sound, it causes the tympanic membrane to vibrate. This vibration causes the ossicles to vibrate also. The footplate of the stapes is in the oval window and when it vibrates the stapes is pushed into the middle ear which contains fluid. This fluid then compresses a little membrane and the movements create an electrical impulse which travels along the vestibulocohlear nerve to the brain for the sound to be interpreted.

Question 23

What is infection of the external ear called? How is it treated?

Answer 23

Otitis externa

Flushing out the ear

Question 24

What is infection of the middle ear called?

Answer 24

Otitis medial

Question 25

Why are middle ear infections more common?

Answer 25

The infection can pass from the nasopharynx (e.g. throat infection) through the auditory tube to the middle ear

Question 26

It can be difficult to clear some otitis media infection. What type of infectiosn are these?

Answer 26

Chronic otits media

Question 27

Chronic otitis media can lead to what problem?

Answer 27

Breakdown of the tympanic membrane leading to pus in getting into the internal acoustic meatus

Patient won’t be able to hear as well as there will be pus around the ossicles

Question 28

What is glue ear also termed?

Answer 28

Chronic otitis media with effusion

Question 29

Describe what happens in chronic otitis media with effusion. How is it treated? What patients does it normally happen in?

Answer 29

Normally in kids

Tend to have a serious of sore thrats and the auditory tube becomes blocked due to swelling of the lymphatix tissues (tubal tonsils). Get a buildup of mucous in middle ear

Kid wont hear as well

Treatment is normally just mointoring the ear and it goes away on its own (if not put ventilation tube in)

Question 30

Surgery to the ear (middle ear) can damage what nerve?

Answer 30

Facial nerve

Question 31

A bad infection in the middle ear might interfere with what nerve?

Answer 31

Facial nerve

Question 32

What ligament holds the stapes in place? What might happen to this ligament?

Answer 32

Angular ligament

Calcium deposition on the ligament which restricts the movement of the stapes and therefore is a cause of deafness