HLTH 2501: the ear Flashcards
external ear
consists of the pinna (auricle) and the external auditory meatus or canal
where does the external ear canal pass through?
the temporal bone to the tympanic membrane
middle ear
consists of the tympanic cavity and the ossicles
what is the stapes in contact with?
the oval window
what does the middle ear open into?
the auditory or eustachian tube and this connects to the nasopharynx
function of the auditory tube
to equalize pressure in the middle ear with the external ear canal
what lines the middle ear cavity?
a continuous mucus membrane
why is spread of infection so easy to the ear?
because of the continuous mucus membrane that connects the middle ear cavity to the nasopharynx
name for the inner ear
the labyrinth
two parts of the inner ear
the cochlea and the semicircular canals
what connects the cochlea and semicircular canals?
a vestibule
cochlea
spiral fluid filled structures that surrounds the organ of corti
where in the brain is sound processed?
the temporal lobe
what determines the loudness of sound?
the height of a wave
what determines the pitch of sound?
the frequency
semicircular canals
found in the inner ear and sense balance and equilibrium in 3 axes
what senses balance and equilibrium in the semicircular canals?
the crista ampullaris
vertigo
is a sense of rotation of self or the environment and is caused by vestibular damage
2 types of hearing loss
conduction deafness and sensorineural deafness
conduction deafness
occurs when sound is blocked in the external ear or the middle ear
examples of causes of conduction deafness
wax or a foreign object in the external ear canal or scar tissue or adhesions near the tympanic membrane
sensorineural deafness
develops with damage to the organ or corti or the auditory nerve
what can sensorineural deafness result from?
infection, sudden loud sounds, prolonged exposure to loud noise, head trauma, or other neurological disorders
common infections causing sensorineural impairment
rubella, influenza, and herpes
drugs and hearing loss
some can cause temporary or permanent damage and include antibiotics like streptomycin, analgesics like aspirin, or the diuretic furosemide
early signs of drug toxicity causing hearing damage?
tinnitus
what can tinnitus be addressed with?
noise suppression therapy and medications like lipo-favonoids
presbycusis
is a sensorineural loss that occurs in elderly people owing to a reduced number of hair cells in the cochlea
treatment for deaf newborns
regular therapy with a speech-language pathologist, lip-reading, sign-language, or assistive devices for communication
cochlear implants
can be successful for sensorineural loss in young deaf children and adults; this works by bypassing structures in the ear to stimulate the auditory nerve directly when this is still functioning; is usually effective when used in young age
otitis media
is an inflammation or infection of the middle ear cavity which is caused by exudate building up and causing pressure on the tympanic membrane
what can occur with otitis media?
the fluid cannot drain into the nasopharynx, and therefore the increased pressure can cause the rupture of the tympanic membrane, which may lead to scar tissue and conductive hearing loss
why is otitis media more common in children?
because their auditory canal is shorter and wider and forms more of a right angle with the nasopharynx, thereby facilitating drainage of respiratory secretions into the auditory tube
common causative agents of otitis media
haemophilus influenzae, pneumococci, beta-hemolytic streptococci, and staphylococci; viral infections may also lead to this when complicated by a secondary bacterial infection
signs of otitis media
earache, red and bulging tympanic membrane, mild hearing loss, fever, nausea, and rupture may cause purulent discharge from the external ear canal
treatment for otitis media
antibiotic treatment is controversial, so ibuprofen or acetaminophen can be used; other options are decongestants, drainage tubes, or chewing gum; surgery may be used if the ossicles adhere to the membrane
cholesteatoma
is a cyst like mass that may develop with chronic otitis media and the accompanying ruptured membrane that is formed by epithelial cells; this may erode the ossicle and impair hearing
otitis externa
aka swimmers ear and is an infection of the external auditory canal and pinna
causes of otitis externa
usually is bacterial and may be caused by swimming, cleaning the ear, or earphones or earplugs
signs of otitis externa
pain, purulent discharge, and a hearing deficit
difference between otitis externa and media
externa will have pinna pain
otosclerosis
involves an imbalance in bone formation and resorption and can cause excess body in the middle ear cavity, causing the stapex to become fixed to the oval window and blocking sound into the cochlea
development of otosclerosis
is genetic and common in young females
treatment for otosclerosis
surgical removal of the stapes and replacement by a prosthesis
meniere syndrome
is an inner ear disorder that affects one ear via excessive endolymph developing, stretching the membranes and interfering with the function of hair cells
meniere syndrome attack
occurs when rupture of the labyrinth membrane allows perilymph to mix with endolymph, increasing the volume
signs of a meniere syndrome attack
severe vertigo, tinnitus, unilateral hearing loss, nausea, sweating, inability to focus, nystagmus, and a feeling of pressure in the ear
what do repeated occurrences of meniere syndrome cause?
permanent damage to the hair cells, with permanent loss of hearing and vertigo
causes of a meniere syndrome attack
stress, changes in barometric pressure, high sodium diet, and smoking, alcohol, or caffeine
tests for meniere syndrome
balance tests, electronystagmography, fluid test, electocochleogprahy tests, and MRI
electronystagmography
evaluates balance by assessing eye movement
fluid test
checks for abnormal buildup in the inner ear
electrocochleography test
responds to sounds
treatment for meniere syndrome attacks
dimenhydrinate, diazepam, or antihistamines
