click below
click below
Normal Size Small Size show me how
Physiology
Hearing
Question | Answer |
---|---|
Eustachian tube | equalize gas pressure in middle ear. more horizontal in young children, which prone to ear infection. |
Cochlea: it is an inner ear contains vistibules, semicircular canal | has two windows: oval window and round window. 3 compartments: vestibular duct which contains perilymph, cochlea duct contains endolymph. organ of corti is located in the middle of cochlea duct. and tympanic duct contains perilymph as well. |
organ of corti: Hair cell | non-neuronmechanoreceptor with stereocilia. it synapse primary sensory neuron, which synapses to cochlea nerve. |
superior to hair cell | is tectorial membrane |
Inferior to hair cell | is baselar membrane |
sound tranduction: part one. stimuli changes form many times | 1.sound waves (1st form) are collected and funneled into inner auditory canal. cerumenous gland produce cerumin for protection. 2) sounds waves hit tympanic membrane causes vibration (2 form. mechanical change) |
Part two | 3. mechanical vibration is transmitted to ossicle ( malleus, incus and stapes) |
Eustachian tube | equalize gas pressure in middle ear. more horizontal in young children, which prone to ear infection. |
Cochlea: it is an inner ear contains vistibules, semicircular canal | has two windows: oval window and round window. 3 compartments: vestibular duct which contains perilymph, cochlea duct contains endolymph. organ of corti is located in the middle of cochlea duct. and tympanic duct contains perilymph as well. |
organ of corti: Hair cell | non-neuronmechanoreceptor with stereocilia. it synapse primary sensory neuron, which synapses to cochlea nerve. |
superior to hair cell | is tectorial membrane |
Inferior to hair cell | is baselar membrane |
sound tranduction: part one. stimuli changes form many times | 1.sound waves (1st form) are collected and funneled into inner auditory canal. cerumenous gland produce cerumin for protection. 2) sounds waves hit tympanic membrane causes vibration (2 form. mechanical change) |
Part two | 3. mechanical vibration is transmitted to ossicle ( malleus, incus and stapes) Stapes attached to oval window.4. it bangs up against oval window of cochlea and causes fluid waves(3th form) in the perilymph of the vestibular duct and down to tympanic duct |
part two | the fluid waves eventually hit the round window (soft and flexible), which dissipate the pressure. 5. meanwhile the fluid waves causes movement of corti in cochlea duct and effect the organ of corti. |
the effect of organ of corti causes: | 1. Causes Tectorial membrane to move down and smash into hair cell and bend the cilia of the hair cell. 2. causes baselar membrane to move up, smashing hair cell into tectorial membrane. Part 6. stereocilia are lossly connected through protein bridges. |
part 6 continue | when pull apart, they open Gated K+ channels, therefore K+ diffuse into the cell causes graded potential--causes action potential, neurotransmitter release to primary sensory neuron. 7. to cochlea nerve--to thalamus to auditory cortex of temporal lobe. |
Pich | Frequency of sound wave( wave length). we measure pitch as herz. |
Low frequency sound | reverberate entire length of baselar membrane, especially at medial end. it stimulates more hair cell, therefore, easier to hear. |
High pitch or frequency sound | only reverberate the lateral end and dissipate. it stimulate less hair cell, therefore, harder to hear |
Loudness | has to do with the height of the wave length.it is an amplitude of sound wave. measures in decibel. increasing amplitude, increase stereocilia bending-- push them further. 80 decibel can cause temporary or permenent damage to hair cell. |
conductive hearing loss | is where sound wave not transmitted through external or middle ear. for example, build-up cerumen, ruptured of tympanic membrane, ossicle, malformed pinna or ear infection. |
sensorineural hearing loss | where the structure of cochlea is damage, either from birth or loudness.correction is hearing aid or cochlea implant. |
central hearing loss | damage to cochlea nerve or auditory cortex. no correction because neuron cannot regenerated. |
Equilibrium or state of balance. Macula | 1.located in vestibule of inner ear.2. detect liner movement of head.3. with lifting of head forward or backward causes otolith to move in responds to cavity.4. pull on otolith membrane.5.bend cilia of hair cell ( the non-neural mechanoreceptor) |
Equilibrium | action potential conducted toward primary sensory neuron synapses in the vestibular or run without synapsing to cerebellum. |
Cristae | is located at the base of the three semicircular canal. it detects rotation acceleration of head. semicircular canal oriented in three plane of space filled with fluid called endolymph. with head movement cause endolymph in semicircular canal to swirl |
cristae continue | bends capula and bends hair cell. |