the ear

Question 1

what are the three components of the external ear?

Answer 1

auricle
external auditory meatus
external surface of the tympanic membrane

Question 2

what are the 4 components of the internal ear?

Answer 2

internal surface of the tympanic membrane
tympanic cavity
ossicles
pharyngotympanic tube

Question 3

what are the 6 components of the inner ear?

Answer 3

auditory apparatus
vestibular apparatus
internal auditory meatus
vestibulochochlear nerve
oval window
round window

Question 4

what forms the boundary between the external and middle ear?

Answer 4

the tympanic membrane

Question 5

where do the middle and inner ear communicate?

Answer 5

at the oval and round window

Question 6

what is the external ear made of?

Answer 6

elastic cartilage

Question 7

what is the function of the auricle?

Answer 7

the auricle functions to catch sound waves and funnel them towards the external auditory meatus

Question 8

where does the auricle receive arterial supply from?

Answer 8

from branches of the external carotid artery

Question 9

explain how sound waves are passed to the middle ear

Answer 9

the tympanic membrane vibrates in response to sound waves hitting the external surface. the malleus ossicle bone attaches to the tympanic membrane and so as the membrane vibrates so does the malleus. this transmits the energy from the sound into a physical energy which can then be passes deeper in the middle ear

Question 10

explain the relation of the ossicles

Answer 10

the handle of the malleus sits on the tympanic membrane

the malleus articulates / the incus bone

the incus bone articulates w/ the stapes

Question 11

what joints are present between the ossicle bones?

Answer 11

plane synovial joins

Question 12

how is sound transmitted to the inner ear?

Answer 12

it passes between the ossicles until it reaches the footplate of the staples which rests against the oval window where it passes through and then deeper into the inner ear

Question 13

what is the oval window?

Answer 13

a membrane covered hole that leads to the inner ear

Question 14

what are the two small muscles in the middle ear?

Answer 14

tensor tympani
stapedius

Question 15

what is the function of tensor tympani and stapedius?

Answer 15

act to dampen the sound being passed from the ossicles to the more delicate structures of the inner ear

Question 16

what is the pyramid of the inner ear?

Answer 16

a small bulge of bone

Question 17

how does the facial nerve enter the temporal bone?

Answer 17

via the internal auditory meatus

Question 18

explain the courses of the facial nerve through the temporal bone

Answer 18

it passes through the petrous temporal bone until it exits the bone at the stylomastoid foramen

Question 19

where does the facial nerve divide into its branches that supply the muscles of facial expression?

Answer 19

at the parotid gland

Question 20

where does the chords tympani branch from?

Answer 20

the facial nerve

Question 21

where does the chords tympani join the lingual nerve?

Answer 21

in the infratemporal fossa

Question 22

where does the auditory tube pass from / to?

Answer 22

it passes from the lateral wall of the nasopharynx (one either side) to open into the middle ear

Question 23

why is the medial part of the auditory tube cartilaginous?

Answer 23

to provide attachment for salpingopharyngeus and tensor and levator veli palatini

Question 24

explain the arterial supply to the middle ear

Answer 24

branches from both the external and internal carotid artery supply blood to the middle ear

Question 25

explain what happens after the stapes vibrates in the oval window

Answer 25

this creates movement of the fluid of the bony and membranous labyrinths which reach the special sense of hearing and balance cells housed in the membrane

Question 26

what is the function of the cochlea?

Answer 26

the cochlea houses the cells that provide the special sense of hearing

Question 27

how do sound waves reach the round window?

Answer 27

the waves pass down the Scala tympani until it reaches the round window

Question 28

what is the final step of the perception of sound?

Answer 28

the cells of the organ of corti (spiral organ) detect movement and transform it into electrical energy (a nerve impulse) which is then passed into the cochlear nerve. this nerve carries the nerve moulds to the brain to be interpreted as dif sounds by the auditory cortex

Question 29

how is balance detected?

Answer 29

the semi circular canals of the bony labyrinth house the semi circular ducts of the membranous labrynth. these ducts house motion sensor cells in their ampullae

motion is detected by waves of movement through the endolymph inside the ampullae, utricle and saccule

movement is detected and nerves fire in response. the nerve impulses pass to the vestibular part of cranial nerve 8 which then passes to the brain for interpretation

Question 30

what are otoloiths?

Answer 30

tiny piece of bone that sit on the receptor cells and move in response to the movement of endolymph

Question 31

where does the vestibulocochlear nerve run from / to?

Answer 31

from the inner ear to the brain

Question 32

explain the arterial supply to the inner ear

Answer 32

there are several vessels that supply the internal ear structures mainly from the auditory artery