Chapter 16 - Ears Flashcards
What is the external ear called?
auricle or pinna
What is the pinna made of?
movable cartilage and skin
What is the role of the external ear?
funnel sound waves into the external auditory canal
Where does the external auditory canal terminate?
tympanic membrane (eardrum)
What do the glands in the ear canal secrete?
cerumen, yellow wax that lubricates and protects the ear
What is the purpose of ear wax?
prevents foreign bodies from entering ear drum
How does ear wax move?
chewing and talking movements
What is the inner ear made of?
bone covered by skin
The outer curve of the ear canal curves _________ and the inner angle ________
upward, downward
What separates external ear and middle ear?
tympanic membrane
What shape is the eardrum?
oval, and slightly concave
What are the ossicles in order?
malleus, incus, stapes
What appearance is the eardrum?
translucent, pearly grey
The umbo, manubrium, and short proces are parts of the ________
malleus
What is the pars flaccida?
the small, slack, superior section of the tympanic membrane
What is the pars tensa?
the thicker and more taut part of the eardrum
What is the annulus?
the outer fibrous rim of the ear drum
Where does lymph fluid of the external ear drain?
into parotid, mastoid, and superficial cervical nodes
Which skull bone is the middle ear located in?
temporal bone
The ossicles are located in which section of the ear?
middle ear
What is the opening at the end of the stapes called?
oval window
What is the eustachian tube?
opening that connects the middle ear to the nasopharynx and allows passage of air
When does the eustachian tube open?
with swallowing or yawning
What are the 3 functions of the middle ear?
-sound conduction from outer ear to hearing apparatus
-protects inner ear by reducing amplitude of loud sounds
-equalization of air pressure to prevent membrane rupture
What is the bony labyrinth?
area in the inner ear that holds the sensory organs for equilibrium and hearing
Where are the vestibule and semicircular canals located?
in the inner ear
Where is the central hearing apparatus located?
the cochlea
Cochlea is latin for…
snail shell
Where is the mastoid process?
bony prominence behind the lobe of the outer ear
What are the 3 levels of the auditory system?
-peripheral
-brain stem
-cerebral cortex
What happens at the peripheral level?
transduction of sound vibrations into electrical impulses
What is amplitude?
loudness
What is frequency?
pitch
What does the basilar membrane do?
vibrates at a point specific to the frequency
What is the senosory organ of hearing?
organ of corti
What is the hearing function at the brain stem level?
binaural interaction
What does binaural interaction allow?
hearing the direction of a sound in a space
What allows for binaural interaction?
each ear is one half of the sensory organ, areas in the brain stem are sensitive to different intensity and timing
What are the two pathways of hearing?
air conduction vs bone conduction
What is conductive hearing loss?
a mechanical dysfunction of the external or middle ear
What can cause conductive hearing loss?
-impacted cerumen
-foreign bodies
-perforated eardrum
-pus or serum in middle ear
-otosclerosis
Otosclerosis
a decrease in mobility of the ossicles
What is another name for sensorineural hearing loss?
perceptive hearing loss
What parts are involved in sensorineural hearing loss?
pathology of inner ear, CN VIII, or auditory areas of cerebral cortex
Presbycusis
gradual nerve degeneration that occurs with aging
What do ototoxic medications affect?
hair cells in the cochlea
What is mixed hearing loss?
combination of conductive and sensorineural hearing loss in the SAME ear
What part of the ear contribute to equilibrium?
3 semicircular canals
Vertigo
spinning, whirling sensation caused by inflamed semicircular canals
At what week of gestation does the inner ear start to develop?
early in the 5th week
Contracting Rubella during the first trimester can damage what in the infant?
organ of Corti
Why is it easier for pathogens from the nasopharynx to travel to the middle ear in infants?
the infants eustachian tube is shorter and wider and more horizontal
The eustachian tube is surrounded by ______ tissue that increases during childhood and can cause occlusion
lymphoid
What is a common cause of conductive hearing loss in young adults (age 20-40)?
otosclerosis
With otosclerosis what becomes fixed in the oval window?
the foot of the stapes
What happens to cilia lining the inner ear with age?
they become coarse and stiff
Why is cerumen drier in older adults?
atrophy of the apocrine glands
What are ceruminolytics?
wax softening agents
Presbycusis
hearing loss that occurs with aging
How often is it recommended to have hearing tested?
every 3 years starting at age 2
Otitis media
middle ear infection
Besides anatomy what factors predispose children to otitis media?
-absence of breast feeding in first 3 months
-second-hand smoke exposure
-day care attendance
-male sex
-pacifier use
-low birth weight
-low socioeconomic status
-formula feeding in supine position
Wet cerumen is more common in individuals of which descent?
african or european
Dry cerumen is more common in individuals of which descent?
asian or indigenous
Audism
a form of discrimination based on persons ability to hear
Otalgia
ear pain
tympanoplasty
insertion of tubes into the ears
Otorrhea
discharge from ear
External otitis has what kind of discharge?
purulent, sanguineous, or watery discharge
Cholesteatoma has what kind of discharge?
dirty yellow or grey discharge with foul odour
Recruitment
a condition in which loss is marked when sound is initially at low intensity but becomes painful when repeated loudly
objective vertigo
people feel as if the room is spinning
subjective vertigo
people feel as if they are spinning
How many episodes of otitis media need to happen for it to be recurrent?
3 episodes in the past 3 months OR 4 in the last year
Darwin’s Tubercule
a small painless nodule at the helix, a congenital variation that is insignificant
Why do you hold the otoscope upside down?
prevent forceful insertion and protect incase of sudden head movement
left oof pg 833
