Physiology of the Auditory and Vestibular Nuclei Flashcards
Contrast endolymph and perilymph.
Endolymph- is K+ Rich and in the scala media
Perilymph- K+ Poor and in the scala vestibular and scala tympani
Distinguish where high pitch sounds and low pitch sounds displace the basilar membrane.
Low pitch goes deeper, high pitch goes shallow.
How does K+ enter the hair cell during a deflection of the stereocilia?
High concentration of K+ in endolymph will lead to facilitated diffusion into the Hair cells from opening of the Ion channels during deflection.
Describe the direction of deflection for depolarization or hyperpolarization of hair cells.
Towards Kinocilia leads to depolarization, away leads to hyperpolarization.
What is the stria vascularis and why is it important?
Stria vascularis maintains the K+ of endolymph, without it there would be no concentration gradient.
Distinguish between inner and outer hair cells.
Inner- One row, primary auditory information
Outer- Three Rows, Contractile, acts as amplifier.
What is the job of the DCN?
Localize sound
What is the job of the VCN?
Temporal and Spectral features of the sound
What is the job of the Superior Olivary Complex?
Accurately localize sound.
What is the job of the MSO?
Generates map of interaural time differences.
What is the Job of the LSO nucleus?
Interaural intensity differences.
What is the job of the Superior Colliculus?
Makes vertical height location.
What is the job of the Inferior Colliculus?
Suppresses echos, finds the horizontal location.
What is the job of the MGN?
Relay Station of the auditory pathway. Maintains the tonotopic map.
What do olivocochlear efferents do?
Helps to focus tone and decrease adaptation. Also can be protective.
Why are otoacoustic emissions important?
Newborn hearing tests, generated from motile outer hair cells.
What can cause Sensorineural Hearing loss?
Noise damage, ototoxic drugs. Injury to inner hair cells will cut off input to CNS.
How does a cochlear prosthesis work?
Prosthesis picks up sound waves, the prosthesis is weaved through the cochlear duct and will stimulate electrically the are that it would respond to with normal hearing.
What does the Utricle preferentially detect?
Horizontal acceleration
What does the Saccule preferetially detect?
Vertical Acceleration
What does the anterior, posterior and horizontal each preferentially detect?
Anterior- forward falls
Posterior- backward falls
Horizontal- Spinning
