21 hearing, equilibrium, smell, and taste

Ear

the outer (external) ear, the middle ear, and the inner (internal) ear

Outer ear

Collects and funnels sound waves → mechanical vibrations by eardrum; auricle, external acoustic meatus; tympanic membrane

Auricle

External appendage composed of elastic connective tissue covered with skin; channels vibrations into ear; pinna; outer rim “helix” and “lobule” inferior to opening

External acoustic meatus

Opening through mastoid area of temporal bone and lines with skin; has wax secreting glands “ceruminous glands”

Tympanic membrane

Eardrum; membrane separating outer and middle ear; coverts sound waves to mechanical vibrations

Middle ear

Air filled cavity (tympanic cavity) within temporal bone housing ossicles transmitting vibrations from eardrum to oval window; auditory ossicles, auditory tube, oval window, round window

Auditory ossicles

Bones forming lever system transmitting and amplifying vibrations; malleus, incus, and stapes

Auditory tube

Eustachian or pharyngotympanic tube; connects tympanic cavity and nasopharynx; opens during yawning and swallowing to equalizing pressure between middle ear and external air

Inner ear

Labyrinth within temporal bone containing mechanoreceptors triggering hearing and equilibrium; bony labyrinth