chapter 10 middle ear Flashcards
mode of operation and function of middle ear
mechanical vibration
impedance matching
selective oval window stim
pressure equalization
Outer ear has ________ energy
acoustic
Middle ear has three ossicle bones
malleus incus and stapes
Middle ear transduces acoustic energy into ________ energy
mechanical
The purpose of the estuchian tube is to match the pressure of the middle ear to the pressure of the _________
outer ear
middle ear makes up for the loss of hearing when going from _____to ______
air
fluid
acute otitis media is ____onset
rapid
oval window
separates middle ear from inner ear
Vibratory connections between ossicular chain and the inner ear are established by the _________
oval window
malleus
The first and largest bone in the ossicular chain of the middle ear, connected to the tympanic membrane and the incus
Incus
the second bone in the ossicular chian, connecting hte malleus to the stapes, resembles an anvil
VIbrating of the tympanic membrane is greater than _______
oval window
stapes
the third and smallest bone in the ossicular chain of the middle ear, connected to the incus and standing in the oval window, resembles a stirrup
A main function of the middle ear is to match the impedance of the air in the external auditory canal of the impedance of the ________
inner ear
Impedance
total opposition to motion
opposition of a system to the flow of energy into it and through it
inner ear is fluid therefore, the middle ear must overcome or math the impedance
function of ossicles
99.9% sound is reflected due to high impedance of fluid in the cochlea
30 dB sound loss from air- fluid impedance mismatch
middle ear bones overcome the loss of sound by increasing sound pressure to 34 dB
tensor tympani muscle
contracts in response to intense acoustic stimulation to protect the ear
innervated by CN V (malleus)
stapedius muslce
normally contracts causing a change in the resting position of the tympanic membrane when either ear is stimulated by an intense sound
innervated by CN VII (stapes)
The muscles that operate in the middle ear are the
tensor tympani
stapedius
acoustic reflex
protection again loud noise damage and reflexively activated by loud noise
compare Eustachian tube in children and adults
children” a shorter smaller less steep tube
The accumulation of fluid in the middle ear is more common in babies that in older children and adults because the Eustachian tube is _______
open and relatively flat
The purpose of PE tubes is to
normalize middle ear pressure
The ossicles start forming at _____ days of gestation
32
otitis media
infection in the middle ear
chorda tympani nerve
is a branch of the facial nerve that passes through the middle ear, sense of taste cranial nenrve VII
disorders of the middle ear can result in _______ hearing loss
conductive
middle ear infections start with _________ pressure
negative
T tube
designed to stay in until removed by doctor
acute suppurative otitits media
infection in the middle ear space fills with pus
cholesteatoma
a tumor occurring in the middle ear and mastoid, that combines fats and epithelium from outside the middle-ear space
can get permanent conductive hearing loss
surgical removal of everything
Mastoidectomy
an operation to remove infected cells of the mastoid, part of the temporal bone.
Tympanoplasty
primary purpose is restoration of the patient’s hearing to as great an extent as possible
otosclerosis
laying down of new bone in the middle ear, usually around the footplate of the stapes. when it interferes with stapedial vibration, it produces a conductive hearing loss.
eustachian tube is located
middle ear to nasopharynx
Negative middle ear pressure is usually caused by some abnormality of the _________
Eustachian tube
Perforation of tympanic membrane can lead to a ______ hearing loss
conductive
