The flashcards below were created by user wvuong on FreezingBlue Flashcards.

  1. Auditory system have...
    tonotopic basis for frequency coding along the length of cochlea and the tympanic membrane
  2. the tympanic membrane does what?
    transduced info to neural signals
  3. Hearing (sounds) are...
    waves of compressed air traveling thru space
  4. sound intensity is
    the sound wave height
  5. pitch is
    the wave frequency
  6. organ of hearing (and equiliibrium) is where?
    in the inner ear where the cochlea and the vestibular apparatus located
  7. pathway sensory ograns. hearing.
    • -sound waves enter the external auditory canal and trigger vibes of tympanic membrane
    • -tympanic membrane induces a vibe of the ossicles
    • -last ossicle, (stapes) transmit amplified vibrations to oval window
    • -vibes induce waves in perilymph of various inner ear chambers
    • -round window absorbs excess energy and prevent wave reverberation
    • -fluid wave is transduced into electrical signal by auditory receptors, organs of corti located on basilar membrane
  8. where are receptors for sound?
    the organ of Corti
  9. Organ of Corti
    • have hair cells that transduce fluid wave to electrical signal
    • -energy of wave causes basilar and vestibular membrane to move, displacing hte cilia from organ of Corti
  10. signal transduction.
    movments of the cilia does what to the what channels?
    • open or close potassium channels
    • also changes state of polarization of hair cell
  11. changes in potassium leakage is due to?
    cilia bending, which triggers changes in neurotransmitters exocytosis
  12. neurotransmitters sends what to where?
    electrical signal to afferent neuron of the cochlear nerve
  13. Louder the sound,
    more the cilia bend, more AP produced
  14. which or wher is the membrane responsible for pitch
    Organs of Corti, which is located near the oval window (more sensitive to high pitch sounds while tip of cochlea respond to love pitch sound)
  15. neural pathways for sounds
    cochlear nerve ==> nucleus in medulla oblongata ==> thalamus ==> auditory cortex in temporal lobe
  16. 3 major auditory relay nuclei of brainstem.
    • cochlear nuclei (same as cn VIII in medulla)
    • superior olivary nuclear complex (integration from both side in pons - important in sound localization major input from AV cochlear nucleus)
    • inferior colliculus (in midbrain)
  17. two audtiory systems..
    • anteroventral cochlear n.
    • dorsal posterior ventral cochlear n.
  18. anteroventral cochlear n
    • superior olivary n. (both sides) ==> lateral lemniscus ==>inferior colliculus
    • important for horizontal location of sounds as well as sound patterns
  19. dorsal posteriorventral cochlear n.
    • lateral lemniscus to inferior colliculus (opp side)
    • important for integration
  20. What notices the difference between low and high frequency?
    superior olivary n. (medial and lateral)
  21. low fre sounds distinguished in space by?
    interaural time difference
  22. high fre sounds distinguished by
    difference in intensity between ears
  23. decussation of auditory nuclei visible in where?
    trapezoid body
  24. olivocochlear bundle regulates?
    flow of auditory info to brain
  25. most auditory path neurons cours in lateral lemniscus in where?
    inferior colliculus
  26. some synapse on nucleus of lateral lemniscus where?
    contralateral inferior colliculus
  27. important site of decussation of the lateral lemniscus
    Probst's Commissure
  28. where is the inferior colliculus
    • the midbrain tectum
    • -central nucleus receives auditory info, which proceed to medial geniculate nucleus of thalamus and primary auditory cortex
    • -neurons in single lamina max. sensitive to similar tonal freq
    • -receives input from superior olivary n, n. of lateral lemniscus (both sides) and dorsal n. with pv cochlear (direct)
    • -project to thalamus thru brachium of inferior colliculus
  29. Medial geniculate nucleus
    • thalamic auditory relay nucleus
    • -major part (ventral division) is tonotopically organized (receives input from central n. of inf coll, which is also tonotopically organized)
    • -MGN also linated - layers max sensitive to similar frequencies
    • -thalamocortical auditory projections (aka auditory radiations)
  30. medial geniculate nucleus have columnar organization of neurons sensitive to...
    • tones of similar freuqencies (isofrequency columns)
    • -binaural columns (interaural intensity differences for localization of high-freq. sounds
    • -have prominent layer 4
  31. Wernicke's Area
    • higher order auditory cortex for the interpretation of language
    • (lang. on L side of brain; interpreting emotional content of lang on R side)
    • -one projection to broca's motor speech area in frontal lobe
  32. vestibular system
    deals with the sensory organs: vestibular
  33. vestibular are
    • ampulae of semicircular canals
    • -Maculae of utricle (linear acceleration) + saccule
    • and endolymph
  34. Endolymph
    gel-like fluid flows over hair cells with movement and deflects them (Ca carbonate crystals ...otoliths)
  35. equilibrium of the semicircular canals
    • ability to detect head position and movment (or acceleration)
    • -change of speed (linear acceleration
    • -turning (rotational acceleration)
  36. What detects thhe change of speed?
    utricle and saccule
  37. what detects turning?
    semi-circular canals
  38. what detects backward-frontward movement?
  39. what detects change relative gravity?
  40. sensory cells have cilia extending into gelatinous material topped by...
  41. receptors in ampulla
    • are hair cells with cilia extruding itno gelatinous mass (cupula)
    • -when head rotates, cupula moves, cilia pulled, APs(vestibular nerve, to cerebellum
  42. where is the vestibular nuclei located?
    • floor of 4th ventricle
    • 4 nuclei: inferior, medial, lateral, superior
    • à ascending projections to VPN of
    • thalamus à 1° vestibular cortex in parietal
    • lobes (just behind the 1° somatic sensory cortex).

    • Can project to nearby parietal areas for integration of info regarding head motion
    • with info from somatic sensory receptors in trunk and limbs.
  43. Head motion is due to?
    vestibular hair
  44. cell receptors of the vestibular system?
    • 4 vestibular n. in rostral medulla and caudal pons
    • -2 descending projec. to sc and extraocular muscles (control movements) to cerebellum

    -2 ascending proj. VPN to thalamus to primary vestibular cortex in parient lobe (for conscious awareness of orientation and motion)
Card Set
Lecture 6
Show Answers