Auditory and Vestibular Systems Flashcards
Term: Sense of sound
Audition
Describe the stimulus for the auditory system
Pressurized sound waves of varying frequencies
Structure: From the pinna to the tympanic membrane
Outer ear
Structure: From the tympanic membrane through the stapes
Middle ear
Structure: Past the stapes and containng the cochlea
Inner ear
3 Middle ear bones
- Malleus
- Incus
- Stapes
Describe the movement of sound waves through the auditory system
Pinna collects sound wave
Sound funneled through external auditory canal
Vibrates tympanic membrane, inner ear bones, oval window
Vibrates fluid in cochlea
Fluid moves and stimulates hair cells
Responses picked up by cochlear nerve
Travels to the cortex
Structure: Contains receptors that recieve sound
Organ of Corti
Describe the function of the partition between the perilymph and enodlymph of the cochlea
The parition forces fluid to move in one direction allowing for continuous sound reception
Describe the structure of the organ of corti
3 outter hair cells are attached to the inner hair cells. The outer hair cells fine tune the inner hair cell which transmits sound
Describe the function of the tectorial membrane
The tectorial membrane is pushed down by the fluid in the cochlea to stimulate the hair cells within the organ of corti
Describe how a hair cell is depolarized
Hair cells have cilia attached by tipplings. The direction of cilia movement determines if the signal is inhibitory or excitatory. As the cilia move/vibrate the tipplings are pulled opening K+ channels. Opening of the K+ channels depolarizes the hair cells letting Ca+ rush in. Neurotransmitters in vesicles then move to the membrane and are released stimulating the postsynaptic cell
Describe the arrangement of sound reception within the cochlea
Tonotopic arrangement
- higher frequencies at the base
- lower frequencies at the apex
ALL frequencies DO NOT stimulate every single hair cells.
3 functions of the auditory system in the CNS
- Activating effect of sound (will wake you up)
- Orienting effect (will move head and eyes to sound)
- Recognition of sound
Pathway: Connection to auditory system increases awareness
Reticular formation
Pathway: Connection to auditory system processes information from both ears allows you to determine where the sound is coming from
Inferior colliculus
Pathway: Connection to the auditory system moves your head and eyes toward sound
Superior colliculus
Pathway: Connection to the auditory system that relays information to the primary auditory cortex
Medial geniculate body
Cortical area: Comprehension of sound
Wernicke’s area
Condition: middle ear bones don’t move well, would NOT benefit from a cochlear implant
Otosclerosis
Condition: Common in children, middle ear infection
Otitis media
Condition: Hearing sound without stimulus to the auditory system
Tinnitus
Condition: Loss of hearing due to pressure on the nerves, may be due to a benign tumor
Acoustic Neruoma
How would you discriminate between and inner ear condition and a cochlear condition?
Use of tuning fork and place it on the mastoid process
Can hear = middle ear problem
Can’t hear = cochlear problem
Describe the cause of age related hearing loss
There is a loss of hair cells/receptors
Acronymn: BPPV
Benign Paroxysmal Positional Vertigo
Top 3 complains to PCP
- Chest pain
- Fatigue
- Dizziness
3 Systems that work together for Balance
- Vestibular
- Vision
- Somatosensory
Location: Vestibular
- Peripheral sensory appartatus
- Central processing system
- Motor system
- Inner ear
- Vestibular nuclei in brainstem
- Ocular/Skeletal muscle
Structure: Provides sensory input about both agnulgar and linear acceleration
(Vestibular) peripheral sensory apparatus