Ears

Question 1

what are the main three components of the ear?

Answer 1

outer ear
middle ear
inner ear

Question 2

what is the external auditory canal lined with?

Answer 2

lateral part - skin, cartilage

medial part - skin, bone

Question 3

what separates the external auditory canal from the middle ear?

Answer 3

tympanic membrane

Question 4

what are the three layers of tympanic membrane?

Answer 4

skin
fibrous layer
respiratory layer

Question 5

what allows a connection between the tympanic membrane and the inner ear?

Answer 5

ossicles

Question 6

what are the three ossicles of the middle ear? where are they?

Answer 6

malleus - attached to tympanic membrane
stapes - attached to oval window of inner ear
incus - in between malleus and stapes

Question 7

what are the two main areas of the tympanic membrane called?

Answer 7

pars flaccida (top)
pars tensa (bottom)

Question 8

what part of which bone surrounds the middle and inner ear?

Answer 8

petrous part of temporal bone

Question 9

with what structures does the middle ear have direct communication?

Answer 9

mastoid process

nasopharynx via eustachian tube

Question 10

what are the two muscles found in the middle ear, and what is their function?

Answer 10

tensor tympani - dampens down loud noises by adjusting tympanic membrane tension
stapedius - stabilises the stapes

Question 11

what does a pinna hematoma lead to?

Answer 11

cauliflower ear

Question 12

which part of the external auditory canal produces wax?

Answer 12

the lateral part

Question 13

what is the difference in appearance between the lateral and medial parts of the external auditory canal?

Answer 13

lateral has cilia and earwax producing glands

medial has no cilia and doesn’t produce wax

Question 14

what is the middle ear lined with?

Answer 14

respiratory epithelium

Question 15

what nerve supplies the inner ear?

Answer 15

vestibulocochlear nerve (CNVIII)

Question 16

what are the three chambers in the cochlea called?

Answer 16

scala vestibuli
scala media
scala tympani

Question 17

what fluid is contained in the chambers of the cochlea?

Answer 17

scala vestibuli - perilymph
scala media - endolymph
scala tympani - perilymph

Question 18

what is the Organ of Corti?

Answer 18

a structure with hair cells which relay soundwave pressure information to the nerve fibres

Question 19

what’s the name of the facial nerve branch which passes through the middle ear?

Answer 19

chorda tympani

Question 20

what is cholesteatoma?

Answer 20

abnormal build up of skin in the middle ear

Question 21

what are 5 important structures near the middle ear, which may be clinically important?

Answer 21

• facial nerve
• mastoid process
• sigmoid sinus/internal jugular vein
• internal carotid artery
• brain

Question 22

what is the general sensory supply to the middle ear?

Answer 22

tympanic branch of glossopharyngeal nerve (CNIX)

Question 23

what is the general sensory supply to the posterior part of the external auditory canal?

Answer 23

auricular branch of vagus (CNX)

Question 24

what is the general sensory supply to the anterior part of the external auditory canal?

Answer 24

facial nerve (CNVII)

Question 25

what are the functions of the inner ear labyrinth?

Answer 25

hearing and balance

Question 26

what are the components of the inner ear involved in balance?

Answer 26

semicircular canals
utricle
saccule

Question 27

what are the functions of the three components of the labyrinth in the inner ear?

Answer 27

semicircular canals - detect head rotation
saccule - detect vertical acceleration
utricle - detect horizontal acceleration

Question 28

what type of sounds are detected at which point of the cochlea and why?

Answer 28

low pitched sounds - at the start (short hair cells)

high pitched sounds - at the end (long hair cells)