Flashcards in Ear Deck (44)
What is human hearing range?
What is the function of the outer ear?
What is the function of the middle ear?
What is the function of the inner ear?
Converts sound into neural impulses.
Give the components of the outer ear.
Auricle, external auditory canal, tympanic membrane
Give the components of the middle ear.
Hammer, anvil, stirrup
Give the components of the inner ear.
Semicircular canals, oval window, cochlea
Where is the middle ear?
Temporal bone of the skull
Which nerve innervates the middle ear?
CN IX : Glossopharyngeal
What connects the middle ear to the pharynx?
Eustachian tube. This exposes the middle ear to atmospheric pressure.
What causes a difference in pressure between the middle and outer ear?
Changes in altitude
Vibrations of the tympanic membrane transmit to the inner ear via which bones?
Ossicles (smallest bones in body) which have synovial joints:
Is the cochlear air or fluid filled?
What membrane lies between the middle and inner ear?
Which muscles in the middle ear control the amount of energy transmitted to the inner ear?
Which nerve innervates tensor tympani?
CN V, V3
Mandibular branch of trigeminal nerve
Which nerve innervates stapedius?
Which bone does tensor tympani attach to?
Which bone does stapedius attach to?
Which membranous tube divides the cochlear lengthwise?
Contains sensory receptors
What fluid does the cochlea duct contain?
Endolymph: high K+, low Na+
What structures lie above and below the cochlear duct?
Above: Scala vestibuli
Below: Scala tympani
Briefly outline the path of sound transmission in the ear.
External acoustic meatus > Tympanic membrane > Ossicles > Oval window >
Scala vestibuli > Cochlear duct > Organ of Corti
What are the receptor cells on the Organ of Corti called?
Hair cells. They are mechanoreceptors that have stereo-cilia. There are inner and outer hair cells.
What is the function of inner hair cells?
Stereo-cilia extend into the endolymph. They convert pressure waves caused by movement of cochlear fluid into receptor potentials.
What is the function of outer hair cells?
Stereo-cilia are embedded in overlying tectorial membrane. They mechanically alter its movement to sharpen frequency tuning.
What are the spiral ganglion and where do they lie?
These are the cell bodies of cochlear nerve fibres. They lie within the cochlea.
Briefly outline the pathway of neural transmission in hearing.
Cochlear nerve > Second order neurones in pons > Superior olivary nucleus > Inferior colliculus of midbrain > Inferior branchium nerve fibre > Medial geniculate body of thalamus > Internal capsule > Primary auditory cortex of temporal lobe
What region of the temporal lobe surrounds the primary auditory cortex?