Auditory pathway Flashcards Preview

Anatomy term 2 > Auditory pathway > Flashcards

Flashcards in Auditory pathway Deck (45)
Loading flashcards...

What is found in the petrous part of the temporal bone? (2)

1. cochlear
2. internal acoustic meatus


What type of energy does the external ear transmit?

sound waves


What type of energy change occurs in the middle ear? (2)

Sound waves to mechanical


What type of energy change occurs in the inner ear? (2)

mechanical to electrical


What cranial nerves run through the internal acoustic meatus?

vesitbulocochlear nerve (CN VIII)

facial nerve (CN VII)


What is the petrous part of the temporal bone like?

very hard


What is the ear drum known as?

tympanic membrane


What does the auditory tube do?

Connects to nasopharynx

enables air passage to maintain equilibrium of pressure

- goes wrong in planes


Why is the middle ear a high risk space? (5)

1. connected to nasopharynx - prone to infection
2. connected to mastoid air cells - infection may spread to middle cranial fossa
3. internal jugular vein lies inferior - thrombosis risk
4. internal carotid artery lies anterior - link to pulsatile tinnitus
5. traversed by chord tympani and facial canal - infection risk


What also increases infection risk especially concerning nerves?

holes which nerves pass through


What is the inner ear?

series of fluid filled cavities


In the inner ear, what are the names of the series of cavities the petrous part of the temporal bone have and what do they contain?

1. vestibule
2. SSC - superior semicircular canal
3. cochlea



Where does the cochlear duct run through and what type of lymph does it contain?

runs through the cochlea

contains endolymph


What is the cochlear duct?

a membranous sac (closed tube) contain endolymph


What is the ion conc like in endolymph?

low sodium

high potassium


Things you need to know in inner ear? (5)

1. posterior semicircular canal and duct
2. vestibule
3. lateral semi-circular canal and duct
4. anterior semicircular canal and duct
5. cochlea


What type of lymph does the cochlea contain?



What two chambers does the cochlear duct separate the cochlea into?

1. scala vestibuli
2. scala tympani


What are the two chambers scala vestibuli and tympani continuous of?

apex of cochlea - helicotrema


How is sound transmitted in the cochlea?

1. hydraulic pressure is created in the perilymph
2. this pressure is created by vibrations of Stapes and pass to apex via the Scala vestibuli
3. the vibrations pass through the helicotrema and descends via the Scala tympani to the round window
4. as fluid moves around the cochlea it deforms the fluid, endolymph in the cochlear duct


What makes up the roof and floor of the cochlear duct?

roof - vestibular membrane

floor - basement membrane


What is the auditory receptor?

The spiral organ (of Corti) on the basilar membrane


What does the spiral organ contain?

hair cells with the tips embedded into the tectorial membrane


What is the spiral organ stimulated by?

the deformation of the cochlear duct by perilymph in the surrounding Scala vestibuli and scala tympani


What components do you need to know of the cochlear duct and the things that surround the cochlear duct?

1. vestibular emmbrane
2. tectorial membrane
3. cochlear nerve
4. spiral ganglion
5. scala tympani
6. basilar membrane
7. spiral organ
8. cochlear duct
9. scala vestibuli


What are primary auditory fibres?

axons of bipolar neurone in spiral ganglion


What do the primary auditory fibres form?

the cochlear nerve which becomes part of the vestibulocochlear nerve - CNVIII


Where does the primary auditory fibres enter?

brainstem at cerebellopontine angle


Where does the primary auditory fibres synapse with secondary neurons?

in ventral and dorsal cochlear nuclei


What are the auditory centres in the brain stem?

1. medial geniculate nucleus of the thalamus
2. inferior collicus
3. superior olivary nucleus
4. cochlear nuceli