11 Ear Flashcards
What are the 3 main parts to the ear
- external ear
- middle ear
- internal ear
what is the auricle also called
pinna
what is the function of the external ear
to gather sound
where does the auricle/pinna channel sound into
external auditory meatus
what is the external auditory meatus made of
- part is made of elastic cartilage
- part is made of bone
what are the only 2 places in the body you’ll find elastic cartilage
- external auditory meatus
- epiglottis
what lines the external auditory meatus
- skin
- little hairs
- ceruminous glands
what is the function of the little hairs in the external auditory meatus
protection
what is the function of the ceruminous glands
produce wax (sticky = protective)
what is inflammation of the skin lining of the external ear called
otitis externa
what is the function of the middle ear
lever system to make bigger vibrations
what is the ear drum known as
tympanic membrane
what covers the tympanic membrane
very thin skin
what instrument do you use to look into an ear with
auriscope
what epithelium lines the middle ear
respiratory
what are the ossicles of the middle ear
- malleus
- incus
- stapes
what does the malleus attach to
- handle attaches to the central part of the tympanic membrane (umbo)
what feature does the auriscope reflectioncreate on the tympanic membrane
cone of light
do middle ear infections tend to be acute or chronic
chronic
why do they tend to be chronic
difficult to clear, tympanic membrane breaks down and pus leaks into auricle.
where does the stapes sit
fenestra vestibuli
what holds the stapes in the fenestra vestibuli
the angular ligament of the stapes
what can be a cause of deafness in the elderly to do with the stapes
calcification of the ligament which stops the ligament from moving
what happens to the sound which is gathered at the external ear
- goes through lever system which amplifies the sound
- tympanic membrane is around 20x the size of the stapes so small vibrations create a lot of movement in the stapes
- this movement presses on the fluid in the internal ear
- fenestra cochliae bulges towards the middle ear to compensate for the movement of fluid (you can’t compress a fluid)
- special receptor cells in the internal ear then move and that turns into electrical signals to the brain
how does new air get into the middle ear
through the auditory tube in the nasopharynx
why does new air need to get into the middle ear
because the lining of the middle ear absorbs the air
what holds the ossicles together and allows them to move
- ligaments hold the ossicles together
- synovial joints allow them to move
what is glue ear also known as
chronic otitis media with effusion
what causes chronic otitis media with effusion
- tends to be young children
- often have had sore throats
- overgrowth of tubal tonsils which blocks auditory tube
- goblet cells become more active and mucous builds up
what is a sign of chronic otitis media with effusion
- air bubble at the typmanic membrane
how does a child with chronic otitis media usually present
deaf in that ear
why does the mucous cause a child with chronic otits media with effusion to be deaf
the mucus stops the ossicles from being able to move
how does chronic otitis media with effusion usually resolve
- grow out of it as tissues get bigger
- tubal tonsil returns to normal size
- mucous gets absorbed by lining
nb a ventilation tube can be used if it doesn’t
what is the area that the ossicles are in called
tympanic cavity
what is next to the tympanic cavity
mastoid antrum
how would you treat infection if it spread to the mastoid antrum
probably surgery
what nerve runs close to the middle ear
facial nerve
what muscle reduces the effects of a very loud sound by securing the handle of the malleus
tensor tympani muscle
what muscle reduces the effects of a very loud sound by securing the upper part of the arch of the stapes
stapedius muscle
what supplies the tensor tympani muscle
CNV
what supplies the stapedius muscle
CNVII
why might sound be louder with facial palsy
because stapedius muscle wouldn’t be working so stapes wouldn’t be held down if a loud sound happened
what are the two parts of the internal ear called
- cochlear
- semicurcular canals
what happens in the cochlear
sound is transmitted into electrical impluses to brain which then interprets the sound
what is the function of the semicircular canals
balance
