Lecture: The Auditory Pathway Flashcards Preview

C&M Term 2 > Lecture: The Auditory Pathway > Flashcards

Flashcards in Lecture: The Auditory Pathway Deck (18):
1

In which part of the temporal bone is the internal acoustic meatus located? give some characteristics

Petrous part
very, very hard
IAM - facial nerve, vestibulocochlear nerve

2

What is the pharyngotympanic (Eustachian) tube?

Connects the middle ear to the nasopharynx
maintains equilibrium in pressure

3

Why is the middle ear a high risk space for infection?

connected to:
the nasopharynx which is prone to infection
mastoid air cells - infection may spread to middle cranial fossa >> encephalitis
Internal jugular vein lies inferior - thrombosis risk
Internal carotid artery - pulsatile tinnitus
Nerves - chorda tympani etc - infection risk

4

What are the fluid filled cavities of the inner ear?

Vestibule
Semi-circular canals (posterior, anterior and lateral)
Cochlea

5

What kind of fluid fills these cavities in the inner ear?

Perilymph
- high in sodium, low in postassium

6

What kind of fluid is contained in the cochlear duct?

Endolymph
- more like intracellular fluid
- high potassium, low sodium

7

What are the names of the chambers created by the cochlear duct?

Scala Vestibuli - above duct
Scala Tympani - below duct

8

What is the name of the apex of the duct where these two chambers are continuous?

Helicotrema

9

What is the entrance and exit to the cochlear called?

Entrance - Oval Window
Exit - Round Window

10

Between which two membranes are the cochlear hair cells located?

Tectorial Membrane - superior
Basement Membrane - inferior

11

Where does the vestibulocochlear nerve enter the brainstem?

Cerebellopontine angle

12

At which level and via which structure does auditory information cross over the midline?

At the level of entry - cerebellopontine angle

Crosses over via Trapezoid Body

13

Along what route does auditory information ascend to the primary auditory cortex?

Spiral Ganglion
Cochlear Nuclei
Superior Olivary Nucleus on other side (via trapezoid body)
Inferior Colliculus
Medial Geniculate Nucleus
Heschl's Gyrus

14

Where is Heschl's Gyrus located?

Superior temporal gyrus
extends deep into the cerebral hemispheres

15

Give some specialisations of the auditory pathway

Polysynaptic
Bilateral - allows us to differentiate timing, loudness and therefore location

16

Which regions of the basilar membrane respond to which types of sound?

Apex responds to Low pitch

sound information of low pitch projects to the anterolateral part of Heschl's Gyrus

17

What are the secondary auditory areas and what are their functions?

Broca's area:
anterior
motor/production of words

Wernicke's area:
posterior
sensory/understanding

18

Describe the descending auditory pathways

typically motor pathways
travels back down the way they came up
send of branches to Tensor Tympani and Muscle of Stapedius

These dampen down loud noise, to prevent damage,
do so by tightening eardrum, holding stapes in place