Auditory System S2M1

  1. What is the Auditory pathway
    • Cochlear nerve
    • Cochlear nuclei
    • Superior Olive complex (via lateral lemniscus)
    • Inferior Colliculus
    • Medial Geniculate body
    • Auditory cortex
  2. What frequency spectrum do humans hear
    20-16,000 Hz (20,000 Hz in children)
  3. Ultrasound
    Above 20 Hz
  4. Intrasound
    Below 20 Hz
  5. What is the threshold of dB for humans before damage begins
    120 dB
  6. Which portion of the cochlea is damaged first
    The base (closet to the oval window) high pitch sounds
  7. How many inner hair cells do we have at birth
  8. How many outer hair cells do we have at birth
  9. The outer hair cells in the cochlear amplify sounds how much
    10,000 times
  10. What is the job of the inner hair cells
    They transmit the amplified signal
  11. Stereocilia in the cochlea are connected how
    Tip links
  12. What causes the K+ and then Ca+ channels to open in the cochlear
    When the tip links are pushed toward the longest cilium in the bundle
  13. When the basilar membrane moves, what else moves
    The entire structure is moved
  14. Outer hair cells have an internal motor molecule called
    Prestin, this contracts the cell according to the frequency
  15. What are the two major groups of drugs that are damaging to hair cells
    • Antibiotics (aminoglycoside, kanamycin)
    • Chemotherapy (cisplatin)
  16. What is a unique ability that the hair cells have that make them useful for testing babies ears
    • They can produce swinging sounds that can be heard by a microphone
    • (Otoacoustic Emission)
  17. What kind of neurons are the Cochlear nerves
    Biopolar neurons
  18. 95% of the spiral ganglion communicates with
    The inner hair cells
  19. What is the ratio of ganglia cells to inner hair cells and outer hair cells
    • 10:1 Inner
    • 1:10 Outer
  20. Where are the ventral and dorsal cochlear nuclei
  21. What makes the Auditory pathways unique
    They can be both ipsilateral and contralateral
  22. What will result from damage to the auditory pathway above the superior olivary nuclei
    There won't be complete deafness due to the bilateral innervation
  23. Where is the primary auditory complex
    Superior temporal gyrus area 41
  24. How is the primary auditory cortex organized
    It has awareness of frequency, loudness, and localization (but not words)
  25. Where is the secondary auditory cortex and associated areas
    Wernickes areas (Br 39, 40)
  26. Wernickes aphasia
    • Patients can speak but it makes no sense (word salad)
    • They cannot understand others words, or their own
  27. What happens to the auditory cortex in deaf people
    It becomes more dedicated to visual information mainly sign language and reading lips
  28. What is the ability to have selective hearing coined
    Cocktail party effect (Efferent Pathway)
  29. What is significant about the ear muscles tensor tympani and stapedius
    They have the ability to limit transmission from the middle ear protecting it from damage by harmful noise (Attenuation reflex)
  30. Hyperacusis
    Sensitivity to loud sounds
  31. Unilateral hearing loss indicates
    A disorder in the ipsilateral outer, middle, or inner ear, CN VIII or the dorsal/ventral cochlear nuclei
  32. If there is a conduction issue with the ear there are problems where
    External or middle ear
  33. If there is a sensorineural problems would be caused by
    Disorders of the cochlea or cochlear nerve
  34. What is the difference between sensorimotor and conductive transmission of sound
    • Sensorimotor involves bone conduction and the sensorimotor pathways
    • Conductive uses air conduction and the normal hearing pathway
  35. Rinne test
    • Air conduction is compared to bone conduction of each ear by using a tuning fork on the mastoid process and then in front of the ear.
    • AC>BC = Normal or sensorineural damage
    • BC>AC = Conductive damage
  36. Webers test
    A patient is asked where the tone sounds are louder with a tuning fork when placed in the midline of the forehead
  37. In the Webers test how are the results read clinically
    • With conductive hearing loss, sound is louder in the affected ear
    • With the sensorineural hearing loss, sound is louder in the normal (unaffected) ear
  38. Tinnitus
    Noise in the absence of external stimuli
  39. What are the two major types of hearing aides
    • One that amplifies sounds
    • Cochlear implants that directly stimulate the nerve
Card Set
Auditory System S2M1