Lecture 25 - Ear

Question 1

Where is the inner ear?

Answer 1

within the petrous part of the temporal bone

Question 2

The outer ear is supported by …

Answer 2

cartilage - except for the lobule which has some fat in it

Question 3

What carries the sound into the ear

Answer 3

external auditory meatus - through to the tympanic membrane

Question 4

tragus is which part of the outer ear?

Answer 4

the bit that hair grows off, in front

Question 5

The external auditory meatus is cartilaginous in which parts?.

Answer 5

lateral 1/3

medial 2/3 is embedded in the temporal bone

Question 6

what releases wax in the ear?

Answer 6

cerumen glands - coats are prevents maceration of skin with water

Question 7

what is sensory to the posteroinferior part of the outer ear?

Answer 7

vagus

Question 8

what is sensory to the anterosuperior part and external surface of tympanic membrane?

Answer 8

Auroculotemporal nerve V3

good example of referred pain, can go to other branches of V3 - e.g to the tongue, inferior teeth

Question 9

tympanic membrane has __ junctions all around it

Answer 9

tight jnctions - no holes, no mechanical energy lost

Question 10

What is the cone of light?

Answer 10

antero-inferior quadrant - reflection is created if normal

if not normal the reflection will be somewhere else to to change in curvature

Question 11

Where is the tympanic cavity proper?

Answer 11

directly medial to the membrane

Question 12

Epitympanic recess is where? what does it communicate with?

Answer 12

superior to the cavity proper

communicates with sinuses in the mastoid

Question 13

where does the auditory tube (pharyngotympanic tube) open in the middle ear

Answer 13

antero-inferior wall - project antero-medially towards to nasopharynx

Question 14

auditory tube is largely..

Answer 14

cartilagenous

Question 15

auditory tube allows equalisation of ..

Answer 15

pressure, only opening to the atmostphere for the middle ear

Question 16

The ossicles from lateral to medial are

Answer 16

malleus
incus
stapes

Question 17

The gradient of the auditory tube is higher in ____

Answer 17

adults - less likely to cause infection compared to kids

Question 18

Tensor tympani hangs off the ____wall

what CN innervates it

Answer 18

anterior - attach to malleus

CN5 - trigeminal

T for tensor, T for trigeminal

Question 19

Stapedius hangs off the ____ wall

what CN innervates it

Answer 19

posterior wall

CN7

Question 20

what is the function of Stapedius and Tensor tympani

Answer 20

dampen really loud sounds

Question 21

Chorda tympani is a branch of the ___ nerve, what does it supply

Answer 21

taste to ant. 2/3 of tongue

runs through middle ear

goes with lingual nerve towards the tongue

very complicated course

Question 22

What is the promontary?

Answer 22

formed by the basal (first) turn of the cochlea

good marker for the two opening to the inner ear: Oval and round window

Question 23

oval window is where energy comes __ to the inner ear

Answer 23

in

Question 24

The internal carotid artery is very close to the

Answer 24

middle ear - can feel pulsations

Question 25

The bony labyrinth is..

Answer 25

the space inside the petrous part of the temporal bone, filled with perilymph

Question 26

The membranous labyrinth..

Answer 26

is one continuous sac which sits suspended in the bony labyrinth itself (within the perilymph).

has its own fluid inside - the endolymph

Question 27

Round window acts a means to allow energy to escape the…

Answer 27

bony labyrinth - energy is transmitted by the mebrane back into the middle ear

Question 28

There are semicirclar canals in the bony labyrinth which provide us with…

Answer 28

information regarding dynamic equilibrium

anterior
horizontal
posterior

Question 29

What is between the cochlea and the semicirclar canals?

Answer 29

the vestibule

Question 30

What are the receptors of the vestibule associated with..

Answer 30

static equilibrium

Question 31

The membranous labyrinth is a ___ __ filled with endolymph

Answer 31

The membranous labyrinth is a closed sac filled with endolymph

Question 32

The ampulla (swellings) at the base of the semiciruclar dcts are responseible for..

Answer 32

dynamic equilibrium - head movements

Question 33

What are the to swellings of the vestibule?

Answer 33

utricle and saccule

Question 34

The vestibular nerve and cochlear nerve come together to form..

Answer 34

CN8

Question 35

the cochlea, if you were to unroll it, projects…

Answer 35

antero-medially

Question 36

frequencies deflect different hair cells in the cochlea duct (within the membranous labyrinth)

This mostly happens at a spot called the …

Answer 36

organ of corti - the strucutre of stuff that transmits the vibrations

Question 37

High frequency sounds stimulate hair cells at the __ of the cochlea

Answer 37

base

Question 38

Low frequency sounds stimulate hair cells at the __ of the cochlea

Answer 38

apex

Question 39

Vibration of ____membrane results in movement of hair cells against _____membrane

Answer 39

Vibration of bascilar membrane results in movement of hair cells against tectorial membrane

Question 40

The auditory/cochlea nerve is part of which canial nerve?

Answer 40

CN8

Question 41

What is the mechanism for dynamic equilibrium?

Answer 41

movement of the endolymph through semicircular ducts into ampulla deflecting cupula and acivating hair cells (sensory receptors)

Question 42

what is the mechanism of static equilibrium?

Answer 42

sesnsory receptors inn th utricle and saccule

movement of otolithic membrane due to gravity activates hair cells in utricle and saccule