Exam 4 Review: Chapter 15: Middle Ear
middle ear - The air-filled space in the temporal bone, lined by a mucous membrane, between the tympanic membrane (eardrum) and the inner ear which contains the three auditory ossicles, which convey vibrations through the oval window to the cochlea; it is connected to the nasopharynx by the pharyngotympanic tube which permits equalization of air pressure on either side of the tympanic membrane. aka tympanum and tympanic cavity.ossicles - A small bone,
especially any of the three bones of the middle ear: the malleus (hammer), incus
(anvil), and stapes (stirrup) which form a lever system for converting the air
vibrations (sound) which move the tympanic membrane into movements of the oval
window which create pressure waves in the perilymph of the scala vestibuli and
scala tympani of the cochlea.
oval window - The oval membrane covering and the opening on the medial
wall of the middle ear to which the base of
the stapes is connected and through which the ossicles of
the ear transmit sound vibrations to the perilymph of the scala vestibuli of the cochlea.
pharyngotympanic tube = auditory tube - A hyaline cartilage tube lined with a mucous membrane which connects the middle ear cavity with the nasopharynx; it aerates the middle ear system and clears mucus from the middle ear into the nasopharynx; opening and closing functions of the tube are physiologically and pathologically important: normal opening of the tube equalizes atmospheric pressure in the middle ear; closing of the tube protects the middle ear from unwanted pressure fluctuations and loud sounds; normal physiological mucociliary clearance drains mucus away from the middle ear into the nasopharynx, thus preventing infection from ascending to the middle ear. aka Eustachian tube.
otitis media - Inflammation of the middle ear, occurring commonly in
children as a result of infection and often causing pain and temporary hearing
loss.
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