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What is the external ear composed of?
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Terms in this set (35)
What is the function of the semicircular canals?To process stimuli that are essential for the maintenance of equilibrium.What is a disease of the semicircular canals?VertigoDeafness can be caused by diseases of which parts of the body?-The ear -cranial nerve 8 -the auditory centers in the brainWhat is infection of the outer ear called?Otitis ExternaWhat causes Otitis externa?-bacterias -viruses (ex: herpesvirus) -fungiWhat is a well-known disease of the external auditory canal?Swimmer's earWhat is a common cause of contact dermatitis of the earlobe?EarringsWhat is the most important consequence of middle ear trauma?Perforation of the tympanic membraneWhat can cause perforation of the tympanic membrane?Direct injury with a sharp object (ex: toothpick)Is impacted cerumen treatable?YES -impacted cerumen = impacted earwaxWhat is serous otitis media?Edema of the eustachian tube with subsequent obstruction of the tube and accumulation of fluid in the inner ear due to infection.What are the three forms in which infection of the ear may present?1) Outer ear (otitis externa) 2) Middle ear (otitis media) 3) Inner ear (otitis interna)How does otosclerosis pathologically affect the ears?-Effects both ears -one ear usually incurs more damage that the other -characterized by the deposition of newly formed bone on both sides of the oval windowDoes otosclerosis affect the acoustic nerve?NOWhat is Meniere's disease?A disorder of the inner ear that can lead to dizzy spells (vertigo) and hearing lossHow does Meniere's disease present clinically?1) Episodic vertigo that lasts 1 hour to several hours, typically subsiding but then recurring after a few hours or days 2) Sensorineural hearing loss for low-frequency sound 3) Tinnitus or ringing in the earsWhat causes conductive hearing loss?External or middle ear lesions -i.e. pathological changes to the auditory canal or tympanic membraneWhat causes hearing loss in the auditory canal?Obstruction (ex: ceruminous plug)What causes sensory hearing loss?cochlear abnormalitiesName an important cause of sensory hearing loss:Noise trauma in the workplaceWhat ototoxic drugs cause deafness?Streptomycin, anti-malaria drugs, and certain diuretics.What is the hearing loss of unknown etiology that affects elderly people?Presbycusis (sensory defect)What causes neural hearing loss?Lesions of cranial nerve 8 or of the central nervous systemWhat is the least common cause of hearing loss?Neural hearing lossWhat are typical causes of neural hearing loss?-neuromas of cranial nerve 8 -multiple sclerosis -cerebrovascular accidents