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Fichas

Hearing

Florence Edwards Animal Health Science 2 BVSc Inglés 134 fichas

Fichas del conjunto (134)

  1. 1What is sound?Regions of compressed (high pressure) and rarefied (low pressure) air caused by vibrations and energy moving through the air
  2. 2What is frequency of sound?Number of sound waves per second
  3. 3What are the units for sound frequency?Hertz (Hz)
  4. 4What audible property of sound is determined by frequency?Pitch
    Low frequency = low pitch
    High frequency = high pitch
  5. 5What is the amplitude of sound?Intensity or loudness
  6. 6What are the units for amplitude of sound?Decibels (dB)
  7. 7What is the range of hearing in humans?Wide range of hearing
    20 Hz - 20 kHz
  8. 8What is the range of amplitudes that can be detcted by humans?Wide range of intensities or amplitudes (dynamic stage)
  9. 9What is the auditory field?Range of audible frequencies and amplitudes for a species
  10. 10What is the consequence of sound levels above the auditory field?Damage and pain
  11. 11What is the consequence of sound levels below the auditory field?Cannot hear
  12. 12What affects the threshold for sound at different amplitudes?Frequency
    More sensitive to sound at certain frequencies
  13. 13At what frequency is the lowest threshold for sound in humans?1-2 kHz (conversation area)
  14. 14What is meant by shifting of the audiometric curve in different species?Hearing more sensitive at different frequencies
  15. 15What structure separates the external and middle ear?Tympanic membrane
  16. 16Which part of the ear contains the ossicles?Middle ear
  17. 17Which part of the ear contains the sensory apparatus?Inner ear
  18. 18Which part of the ear is known as the 'conductive zone'?External and middle ear
  19. 19Describe how sound waves are conducted to the inner earSound vibrates tympanic membrane
    Ossicles move
    Press on membrane that marks entrance to inner ear (oval window)
  20. 20What is impedance matching?Difference in surface area between the tympanic membrane and oval window causes amplification
  21. 21Why is impedance matching important?Amplification required as more energy required to move fluid than air
  22. 22What percentage of sound energy would be transferred without impedance matching?0.1%
  23. 23Which 2 muscles are involved in the ossicular reflex?Stapedius
    Tensor tympani
  24. 24What is the location of the muscles involved in the ossicular reflex?Connect ossicles to outer bones of the ear
  25. 25What is the function of the ossicular reflex?Protective against loud sounds above 70 dB
  26. 26How do the muscles of the middle ear carry out the ossicular reflex?Loud sound causes sustained shortening of muscles
    Stiffen levers to reduce energy conduction
  27. 27Why can the ossicular reflex be useful with lots of low frequency noise present?Aids discrimination
  28. 28Above which frequency does the ossicular reflex not have a role in humans?1-2 kHz
  29. 29Why is the ossicular reflex ineffective for impulse noise?50-100 ms delay
  30. 30What is the shape of the mammalian cochlea?Compartmentalised spiral
  31. 31What is the size of the cochlear spiral in man?35 mm
  32. 32Why are altricial species often born deaf?Cochlea partially developed at birth
  33. 33What is the term for the auditory epithelium?Organ of Corti
  34. 34Where is the auditory epithelium located?Flexible basilar membrane
  35. 35How many rows of outer and inner hair cells are there?3 rows outer
    1 row inner
  36. 36Where are the cell bodies of the nerves innervating the auditory hair cells located?Spiral ganglion
  37. 37How are hair cells held rigidly?Supporting cells
  38. 38What is the main specialisation of sensory hair cells?Stereocilia
  39. 39What is the difference in potassium ion composition in perilymph and endolymph?Endolymph high K+
    Perilymph low K+
  40. 40What is the electrical potential of endolymph?80 mV
  41. 41What is the electrical potential of perilymph?0 mV
  42. 42What is the location of endolymph?Bathes stereocilia
  43. 43What is the location of perilymph?Bathes basolateral membrane of hair cells
  44. 44How are endolymph and perilymph kept separate in the cochlea?Compartmentalisation
  45. 45What prevents endolymph leakage through the hair cells?Tight junctions
  46. 46What is the difference in the arrangement of hair cells in birds?Not arranged in rows
  47. 47What is different about the ossicles in birds?1 ossicle called the columella
  48. 48What organ do birds have instead of the organ of Corti?Basilar papilla
    Same function as organ of Corti but not coiled
  49. 49What are the 2 types of hair cells in birds?Long and short
  50. 50What is the arrangment of stereocilia in inner hair cells?Flat rows
  51. 51What is the arrangement of stereocilia in outer hair cells?V-shaped rows
  52. 52Are all stereocilia the same length?No - stepped arrangement with different lengths of stereocilia
  53. 53What are It channels of hair cells?Transduction channels
  54. 54Which channels are found in inner hair cells?IK - transport potassium out of cell
    L-type calcium channels
  55. 55Which channels are found in outer hair cells?IK
  56. 56Do inner or outer hair cells have the most afferent innervation?Inner hair cells
  57. 57What is the name of the motor protein within outer hair cells?Prestin
  58. 58Do inner or outer hair cells receive most efferent innervation?Outer hair cells
  59. 59Which neurotransmitter is found at the efferent synapses of outer hair cells?Acetylcholine
  60. 60How does movement of endolymph cause movement of hair cells?Movement of fluid by ossicles causes movement of basilar membrane
    Hair cells move with basilar membrane
    Tectorial membrane in which stereocilia are embedded remains still
    Shearing of stereocilia against tectorial membrane = displacement
  61. 61Describe how movement of stereocilia induces action potentials in the afferent neuroneTip links connect stereocilia
    Displacement causes tip links to open mechanically gated transduction channels
    High potassium enters cell = depolarisation
    Stimulates opening of Ca2+ channels
    Ca2+ influx releases neurotransmitter
  62. 62What type of channel is the mechanically gated transducrtion channel?Non-specific cation channel
  63. 63Approximately how many inner hair cells are there?3500
  64. 64How many afferent terminals are there per inner hair cell?10-20
  65. 65What channel is characteristic of inner hair cells?Inward calcium channels (L-type Ca2+)
  66. 66What is the function of inner hair cells?Encode sound
  67. 67What is the electrical potential of the inner hair cell?-55 mV
  68. 68What is the electrical potential of the endolymph?+80 mV
  69. 69What is the quantitative driving force for potassium entry into the inner hair cell?135 mV
  70. 70What is the movement of inner hair cells required for perceptible sound?0.3 nm
  71. 71At what displacement do inner hair cells become saturated?20 nm
  72. 72What is meant by tonic activity in inner hair cells?Some transducer current present at rest
  73. 73What is the effect of displacement of inner hair cells in the positive direction?Depolarisation
    Increase in transducer current
  74. 74What is the effect of displacement of inner hair cells in the negative direction?Hyperpolarisation
    Decrease in transducer current
  75. 75What is the effect of different displacement directions on receptor activity?Wave of positive and negative activity
  76. 76What is meant by phase locking?Action potential frequency linked to phase and frequency of stimulus wave
  77. 77How does phase locking occur?Increase in graded receptor potential
    More calcium influx
    More neurotransmitter released
    Increase in action potential frequency
  78. 78What is tonotopy?Spatial arrangement of sound perception
  79. 79How does the structure of the basilar membrane enable tonotopy to occur?Basilar membrane has regional variations in fibrous structure
    Therefore, region of maximum displacement depends on frequency of stimulus
  80. 80What is the effect of low frequency sounds on basilar membrane displacement?Closer to apex
  81. 81What is the effect of high frequency sounds on basilar membrane displacement?Closer to base
  82. 82Where in the hearing apparatus is tonotopy set up?Cochlea
  83. 83Where in the auditory pathways is tonotopy maintained?All the way to cortex
  84. 84What is the function of tonotopic maps?Spectral analysis of sounds
  85. 85How does tonotopy occur in the auditory cortex?Isofrequency maps
  86. 86Where are tonotopic maps found as well as the auditory cortex?Superior colliculus
  87. 87How is tonotopy generated in hair cells?Maximally displaced at certain specific frequencies
  88. 88How is tonotopy maintained in afferent nerves?Characteristic frequency
  89. 89How is sound amplitude encoded?Populations of afferent nerves - high, medium and low spontaneous rate fibres
  90. 90What are high spontaneous rate fibres?Activates at low sound levels and easily saturated
  91. 91What are medium spontaneous rate fibres?Activated at medium sound levels
  92. 92Do medium spontaneous rate fibres saturate?Yes, but at higher sound levels than high spontaneous rate fibres
  93. 93What are low spontaneous rate fibres?Activated when sound levels are high
  94. 94What is the function of low spontaneous rate fibres?Can detect changes in sound at very high sound levels
  95. 95How many afferent synapses are there per inner hair cell?10-20 afferent synapses
  96. 96Approximately how many outer hair cells are there?12 000
  97. 97What is the shape of hair bundles on outer hair cells?V or W shaped
  98. 98Do outer hair cells mainly receive afferent or efferent innervation?Efferent
  99. 99What is the name of the motor protein in lateral membranes of outer hair cells?Prestin
  100. 100Which neurotransmitter is present at efferent synapses of outer hair cells?Acetylcholine
  101. 101Which channels are present in outer hair cells?IT = transduction channel
    IK = outward potassium channels
    No calcium channels
  102. 102What is the function of outer hair cells?Amplification and tuning
  103. 103What is meant by tuning of auditory receptors?Response to lower frequency range
  104. 104How do outer hair cells allow amplification?Depolarisation activates motor protein prestin
    Contraction of outer hair cells
    Pulls on basilar membrane and amplifies movement of membrane
    Increased hair cell activation = amplification
  105. 105How do outer hair cells allow frequency?Pulling on basilar membrane
    Sharper peak = narrower frequency range activated
    Greater frequency discrimination
  106. 106Which system modulates amplification and tuning by outer hair cells?Efferent system
  107. 107What are the consequences of loss of outer hair cells?Hearing loss (loss of amplification effect)
    Poor frequency discrimination
  108. 108What is the quantitative hearing loss that occurs with loss of outer hair cells?60 dB
  109. 109What are otacoustic emissions?Sound reflecting back through the ear
  110. 110What causes otacoustic emissions?Activity in outer hair cells
  111. 111What is the clinical relevance of otacoustic emissions?Diagnosis
  112. 112List the pathway nerves take from cochlea to auditory cortexSpiral ganglion
    Ventral cochlear nucleus
    Superior olive
    Inferior colliculus
    Medial geniculate nucleus of hypothalamus
    Auditory cortex
  113. 113What happens to auditory nerves at the ventral cochlear nucleusBifurcation to ipsilateral and contralateral superior olive
  114. 114What is meant by the binaural auditory pathway?Information from both ears reaches a neuronal population
  115. 115At what level does the auditory pathway become binaural?Superior olive
  116. 116How are low frequency sounds localised?Comparison of time at which same phase of a sound arrives at each ear - there is an interaural delay of the wave peak
  117. 117Where does information from each ear converge?Superior olive
  118. 118How are high frequency sounds localised?Interaural intensity difference
  119. 119How is rotational location of sound (e.g. in front or behind) determined by the pinnae?Mobile pinnae
  120. 120How is elevation of sound (up or down) determined by the pinnae?Folded pinnae
    Combined properties of direct and reflected sound characteristic of elevation
  121. 121Which part of the ear is affected in conductive deafness?External or middle ear
  122. 122What is the main cause of sensorineural deafness?Loss of hair cells and/or neurones
  123. 123Which part of the ear is affected in sensorineural deafness?Inner
  124. 124Give 3 reasons why a dog may develop sensorineural deafnessCongenital - associated with certain breeds
    Noise damage
    Ototoxic drugs which are toxic to hair cells
  125. 125Give an example of an ototoxic drugAminoglycoside antibiotics
  126. 126Which animals can replace their sensory hair cells?Mammals do not replace their sensory hair cells
    Birds and lower vertebrates do
  127. 127Will loss of outer hair cells cause sensorineural deafness?No - some residual hearing will remain
  128. 128How can congenital deafness manifest?Can be born deaf or can be progressive
  129. 129Which specific function in the inner ear is usually disrupted in congenital deafness?Maintenance of endolymph
  130. 130How can an animal's appearance be associated with deafness?Lack of pigmentaton - pale irises and white coats
  131. 131What is Preyer's reflex?Response to sound with movement
  132. 132How does Preyer's reflex manifest in dogs?Elevation and rotation of pinnae
  133. 133What is the most objective diagnostic test for deafness?Brainstem auditory evoked response
    Electrodes placed on head and used to detect neural activity in response to auditory stimulus
  134. 134In what context is the objective diagnostic test for deafness most often used?Screening for breeding programmes in referral practices

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BVSc (Special Senses) Animal Health Science 2 Fichas sobre Hearing, creado por Florence Edwards el 22/02/2017.
Creado por
Florence Edwards · feb 2017
Actualizado
6 abr 2018
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