ALMOST FINISHED Auditory System Flashcards
Missing vestibular pathway
What are the three ossicles of the middle ear?
Malleus, incus, and stapes
What is the function of the tensor tympani muscle?
Dampens low tones by pulling on the malleus internally, thereby increasing the tension on the tympanic membrane
The tensor tympani is innervated by which nerve?
CN V
What is the function of the stapedius muscle?
Decreases sound intensity by pulling the stapes away from the opening into the inner ear
What are the two openings between the cochlea and the middle ear?
Oval window and round window
The oval window opens into what structure of the cochlea?
Scala vestibuli
The round window opens into what structure of the cochlea?
Scala tympani
The stapedius muscle is innervated by which nerve?
CN VII
What structure separates the scala vestibuli and cochlear duct?
Vestibular membrane (Reissner membrane)
What structure separates the scala tympani and the cochlear duct?
Basilar membrane
At what portion of the spiral organ do hair cells respond to high frequency sounds?
Near the base
At what portion of the spiral organ do hair cells respond to low frequency sounds?
Near the apex
Why does damage to CN VII cause hyperacusis?
Loss of function of the stapedius muscle, which decreases sound intensity
The auditory pathways consist of which five structures?
Spiral ganglion, cochlear nuclei, superior olivary nucleus, inferior colliculys, and the medial geniculate nucleus
Where do the auditory pathways terminate?
Transverse temporal gyrus of Heschi
Damage to which portion of the auditory pathways result in ipsilateral hearing deficits?
Cochlea, spiral ganglion, cochlear nerve, or cochlear nuclei
Lesions above the cochlear nuclei result in what kind of hearing alterations?
Poor sound localization, but bilateral hearing remains intact (only mild deficits)
What are the common causes of conduction hearing loss?
Infection, congenital, foreign body or wax, perforated eardrum, otosclerosis, and cholesteatoma
What is conduction hearing loss?
Interference with sound wave passage through external or middle ear
What is sensorineural hearing loss?
Damage to inner ear (hair cells, cochlear nerve, etc.)
What is otosclerosis?
Overgrown of the stapes bone, which interferes with its connection to the oval window
What is a cholesteatoma?
Overgrown of keratin debris in the middle ear space, which may erode internal structures
What aspect of hearing is tested with the Rinne test?
Conduction
What aspect of hearing is tested with the Weber test?
Localization
What Rinne test results do you see in a person with normal hearing?
Air > bone
What Weber test results do you see in a person with normal hearing?
Midline
What Rinne test results do you see in a person with sensorineural hearing loss?
Air > bone, but not as loudly in affected ear
What Weber test results do you see in a person with sensorineural hearing loss?
Sound localizes to normal ear
What Rinne test results do you see in a person with conductive hearing loss?
Bone > air
What Weber test results do you see in a person with conductive hearing loss?
Sound localizes to affected ear
What are the common causes of sensorineural hearing loss?
Loud noise, head trauma, viral, autoimmune, antibiotics, diuretics, Meniere disease, presbycusis, tumors (acoustic neuroma)
What are the two common causes of peripheral vertigo?
Meniere disease and benign paroxysymal postural vertigo
What is the pathophysiological mechanism of Meniere disease?
Peripheral vestibular and auditory apparatus is damaged by increased endolymphatic pressure, which gradually destroys hair cells in the vestibular and auditory peripheral systems
What are the symptoms of Meniere disease?
Abrupt attacks of severe vertigo with nausea and vomiting, tinnitus, and progressive sensorineural deafness
What is the treatment for Meniere disease?
Diuretics, low sodium diet, anti-histaminics
What is the pathophysiological mechanism of BPPV?
Otoconia are displaced from the urticle or saccule into the semicircular canals, interfering with the macula and causing vertigo
What is the treatment for BPPV?
Epley maneuver
