Auditory System Flashcards
What are the 3 fluid-filled cavities of the cochlea?
Reissner’s membrane
Basilar membrne
Transduction
Where is the Scala media closed off at?
The apex
What connects the Scala tympani and the Scala vestibuli?
helicotrema
What is continuous at the Scala tympani and the Scala Vestibuli?
Perilymph
What meets the round window?
Scala vestibuli
What meets at the oval window?
Scala tympani
Describe the Basilar Membrane
Flexible
Vibrates in sync with fluid motion
What determines the distance that a particular frequency travels?
The width and flexibility of the basilar membrane
What opens the TRPA1 channels?
Force towards kinocilium
What connects transduction channels (Cation channels on hairs)
Tip links
What inputs do inner hair cells receive?
Afferent
What inputs do outer hair cells receive?
Efferent
What is the motor protein composed of?
Prestin
What does Furosemide affect?
Inactivates the membrane motor so reveals its influence
What is endolymphs potential?
80mV
What potential is generated to the sterocilia membrane?
120 mV
Is there higher or lower Potassium levels in the endolymph?
Higher
What are the two coding systems for the auditory nerve?
Place code
Temporal code
What frequency level does Place code do?
Higher frequency
What frequency does Temporal code do?
In the brain, what is the pathway from ear end?
CN VIII Trapeziod body medulla Intermediate acoustic site Superior olivary nuclei nucleus of the lateral lemniscus Inferior colliculus Medial geniculate nucleus Primary auditory cortex
What are the 3 branches of the VIII nerve?
Dorsal Cochlear Nucleus (DCN)
Posteroventral Cochlear Nucleus (PVCN)
Anteroventral Cochlear Nucleus (AVCN)
What does tonotopy ensure?
Each neurone innervates several different areas and different neuron types
What do the semicircular canals measure?
Head angular acceleration (head rotation)
What do the saccule and the utricle measure?
Head linear acceleration (Translation motion and Gravity)
What are the saccule and the utricle known as?
The Otolith organs/Otocysts
What does cochlea vibration and labyrinth acceleration/gravity do?
Deforms the hair cells
What does deformation of hair cells do?
Generates an electrochemical signal which is transmitted by nerve fibres to the vestibular nucleus
What does deformation of the stereocilia towards kinocilium cause?
Depolarization
In the semicircular canals, what is the Crista?
Sheet of cells where hair cells are clustered
What does the fluid displace when there is movement?
The capula
Where is the Crista?
In the Ampulla
What does the posterior canal share a plane with?
Contralateral anterior canal
What movement does the saccule measure?
Vertical/Sagittal plane
What movement does the utricle measure?
Horizontal plane
In the otolith organs, where do the hair cells lie?
In the macula
what divides the hair cells into two groups?
The striola
What are present on the otolith membrane?
Crystals of calcium carbonate called Otocania
What is the Vestibulo-ocular reflex?
Keeps the eyes still in space when the head moves
What is the Vestibulo-colic reflex?
Keeps head still in space on level plane when you walk
What is the Vestibular-spinal reflex?
Adjusts posture for rapid changes in position
