The Ear

Question 1

what is the main osteological part of the ear?

Answer 1

pectoris temporal bone

Question 2

what are the three parts of the human ear?

Answer 2

• external ear
• middle ear
• internal ear

Question 3

what is the function of the ear?

Answer 3

organ of hearing and balance

Question 4

what makes up the external ear? what is the function?

Answer 4

Auricle & External Acoustic Meatus
- directs sound waves toward tympanic membrane/inner ear

Question 5

what makes up the middle ear? what is their function?

Answer 5

Ossicles
- mechanically transmit sound

Question 6

what part of the ear is connected to the nasopharynx?

Answer 6

The middle part of ear via the auditory tube

Question 7

what is found within the internal ear? what is their function?

Answer 7

Semi-circular Canals
- motion

Cochlea
- hearing

Question 8

how are mechanical signals conveyed by the ossicles transmitted?

Answer 8

via CNVIII (vestibulocochlear) towards brain

Question 9

what is the visible part of the ear called?

Answer 9

auricle

Question 10

what is the auricle composed of?

Answer 10

elastic cartilage

Question 11

how long roughly is the external acoustic meatus?

Answer 11

2.5cm long

Question 12

what is the lateral 1/3rd of the external acoustic meatus composed of?

Answer 12

cartilage

Question 13

what is the medial 2/3rds of the external acoustic meatus composed of?

Answer 13

bone

Question 14

what epithelium is found in the external ear?

Answer 14

stratified squamous epithelium

Question 15

what is the located in the dermis of the external ear?

Answer 15

• hair follicles
• glands
• ceruminous glands
• blood vessels
• nerves

Question 16

what are ceruminous glands?

Answer 16

modified sweat glands that secrete ear wax

Question 17

how is the tympanic membrane held within the temporal bone?

Answer 17

fibrocartilaginous ring

Question 18

what is the tympanic membrane?

Answer 18

an oval, semitransparent structure situated between the external auditory meatus & the tympanic cavity of middle ear

Question 19

name the ossicles of the ear:

Answer 19

• malleus
• incus
• stapes

Question 20

what is the function of the auditory tube?

Answer 20

connects middle ear with the nasopharynx and allows for pressure equalisation between the middle ear & atmospheric pressure

Question 21

why can respiratory infections sometimes cause problems with the ear?

Answer 21

the auditory tube is a potential route for the spread of infection from the nasopharynx to the ear

Question 22

where does the facial nerve enter the petrous temporal bone?

Answer 22

internal acoustic meatus

Question 23

what branches does the facial nerve give off during its course though the middle ear?

Answer 23

• greater petrosal nerve
• chorda tympani nerve

Question 24

what is the function of the greater petrosal nerve (that comes off of the facial nerve)?

Answer 24

carries parasympathetic fibres to the pterygopalatine ganglion to stimulate the parotid gland

Question 25

the roof of the middle ear is very thin, what clinical implication can this lead to?

Answer 25

any infections of the ear can spread into the cranial cavity

Question 26

what nerve runs along the upper portion of the tympanic membrane?

Answer 26

chorda tympani

Question 27

what is the clinical name for a middle ear infection?

Answer 27

otitis media

Question 28

what is otitis media with effusion?

Answer 28

ear infection that causes a build up of fluid in the middle ear behind the tympanic membrane

Question 29

how may otitis media with effusion be treated?

Answer 29

a grommet may be placed

Question 30

what can chronic infections of the middle ear lead to?

Answer 30

- conductive deafness due to damage of the ossicles - mastoiditis

Question 31

if a patient requires surgery to the middle ear, why is this potentially dangerous?

Answer 31

close proximity to facial nerve

Question 32

what is the bony labyrinth?

Answer 32

the fluid filled space located around the otic capsule

Question 33

what part of the internal ear is concerned with hearing?

Answer 33

the cochlea

Question 34

what parts of the inner ear are concerned with balancing?

Answer 34

- vestibule - semicircular canals

Question 35

what fluid is located in the bony labyrinth?

Answer 35

perilymph that contains endolymph

Question 36

what is the function of the vestibulocochlear nerve?

Answer 36

conveys the sensation of motion and hearing - split into two parts

Question 37

what are the divisions of the vestibulocochlear nerve & their functions?

Answer 37

Cochlear part = hearing part Vestibular part = equilibrium and balance

Question 38

what are the different types of hearing loss?

Answer 38

- neural hearing loss - conductive hearing loss

Question 39

how can neural hearing loss occur?

Answer 39

damage to the cochlear part of CNVIII

Question 40

what can damage to the vestibular part of CNVIII cause?

Answer 40

- ataxia - vertigo - nausea (bc its responsible for balance & equilibrium maintenance)

Question 41

what bone lies in the fenestra vestibuli?

Answer 41

the stapes

Question 42

what can be used to examine the tympanic membrane?

Answer 42

otoscope

Question 43

what may enlarged & tender lymph nodes indicate?

Answer 43

infection present

Question 44

what may hard, painless enlarged lymph nodes suggest?

Answer 44

malignancy