Audation Flashcards
Amplitude
Loudness
Frequency
Pitch
Complexity
Timber
Presbycusis
Hearing loss with age
What range does human hearing occur
20 Hz to 20kHz
Function of external ear
Boost sound by 3 kHz
Conduction
Function of ossicles
Mechanical advanage to amplify sound
Name 2 attenuative muscles
Tensor typanis (CN V) Stapeds (CN VII)
Where is perilymph found in the inner ear
Scala Vestibuli and Tympani
Where is endolymph found in the inner ear
Scala media
Which end of the basilar membrane is narrow & stiff, it is goud at detecting
Side nearest the round window
Detects high frequency sounds
Which end of the basilar membrane is wide & floppy, it is goud at detecting
Side in helicotrema
Detects low frequency sounds
Which has high K concentration
Endolymph (80 mV)
Function of inner hair cells
Movement send information to afferent nerve fibers of CN VIII
Role of outer hair cells
Electromotile, stiffen basilar membrane
Steps in depolarization
Basilar membrane moves
Bend towards tallest kinocilia
K+ enters the outer hair cells from endolymph
Open Ca channels
Neurotransmission release
Outer hair cells elongate to loosen basilar membrane
Cholea amplifiers
K leaves through base of cell so no accumation = quick reset
Steps in hyperpolarization
Basilar membrane moves Stereocilia on outer & inner hair cells move away from the tallest kinocillia Reduced K influx from endolymph Reduced Ca release Reduced NT release Outer membrane hair cells lengthen Basilar membrane stiffens
Steps in auditory pathway
CN 8 Dorsal cochlear in rostral medulla Superior Olive Inferior colliculus Thalamus (Medial Geniculate Nucleus) Auditory Cortex
What happens in dorsal chochlea/rostral medulla
Frequency deduced from ipsilateral side
What happens in Antero\postero ventral medulla
Intensity & loudness deduced
What happens in Superior olive
Medial:
Lateral:
Sound localization
Medial: Time delay
Lateral: Intensity difference
What happens in somatosensory nucleus
Integration of wound with somatosensory inforation
- Startle reflex
- Vestibuloccular Reflex
Filtering background noise
Where in the thalamus does auditory information go
Medial Geniculate Nucleus
Brocha area
Speech production
Wernicke’s Area
Speech comprehension
Supramarginal gyrus
Matching auditory phenoms with meaning
Angular gyrus
Matching written phenoms with meaning
Arcuate Fasiculus
Matches broca & warnicke’s area (involved in conduction aphasia
McGurk Effect
Mismatch between visual & auditory information but visual trumps
Ventral stream in cortext
Pitch
Primary auditory cortex
Inferior Frontal gyrus
Dorsal Stream
Sound locaization
Organization of primary auditory cortex
By frequency in columns in superior temporal gyrus
Secondary auditory cortex recognizes
Combinations of sound
Which hemisphere
Pitch
Left (Broca’s area)
Changes in pitch
Right
Timbre
Right
Hyperbycussis
Hypersensitivity to loud sounds
Auditory agnosia
No meaning attached to non-verbal sound
Congentital amunusia
Tone deafness
Tinnitus
Perception of sound in the absence of sound
Conduction deafness
Can’t conduct sound from the inside
Nerve deafness
Loss of hair cells
Acquired hearing loss caused by which 2 antibiotics
Streptomycin
Gentamicin
Acoustic neuroma
Slow growing tumor from schwan cells
Menieres disease
Progressive hearing loss
Furosemide
Hair cell contraction, sense of sound or hearing loss
