Chapter 13

The ear is considered part of the nervous system and has the following functions:

It allows hearing to occur by picking up sound waves and sending them to the brain. It helps maintain a person's balance.

Semicircular canals

Located behind the vestibule are three bony structures, filled with fluid, that also help to maintain balance.

Vestibule

The central portion of the inner ear, this structure contains the utricle and the saccule, which are membranous sacs that aid in maintaining balance.

Cochlea

This snail-shaped, bony structure contains endolymph and perilymph

Otorrhea

a discharge from the external ear.

Otosclerosis

a growth of spongy bone in the inner ear.

cochlear duct

a membranous structure that aids in the hearing process.

middle ear

also known as the tympanic cavity; found in the temporal bone and houses the auditory ossicles.

Incus

anvil

labyrinth

bony and membranous structures of the inner ear.

eustachian tube

connects the bony structures of the middle ear to the pharynx; also known as the auditory tube/pharyngotympanic tube The purpose of the eustachian tube is to equalize air pressure in the middle ear.

bony labyrinth

consists of bones that make up the inner ear.

cerumen

ear wax helps protect and lubricate the ear. In combination with the cilia, the cerumen helps to protect the eardrum from foreign objects.

Otalgia

earache

semicircular ducts

found in the middle ear; aid in balance.

Malleus

hammer

Otorrhagia

hemorrhage from the ear.

Membranous labyrinth

is a term used to describe the utricle, saccule, semicircular ducts, and cochlear ducts because these structures are all membranous structures.

auricle

known as the pinna or earlobe that allows sound waves to enter the ear canal

saccule

membranous sac that aids in maintaining balance.

endolymph

one of the auditory fluids found in the cochlea that aid in hearing.

perilymph

one of two auditory fluids found in the inner ear that aid in the transmission of sound.

Stapes

stirrup

ceruminous glands

sweat glands found in the external auditory canal. secrete ear wax

external auditory canal

the canal that allows sound waves to travel to the inner part of the ear; also known as the external auditory meatus.

tympanic membrane

the eardrum. separates the external ear from the middle ear The membrane transmits sound vibrations to the inner ear through the auditory ossicles

otitis externa

the inflammation of the external auditory canal.

utricle

the structure of the inner ear that aids in maintaining balance.

auditory ossicles

the three small bones that transmit sound waves.

organ of Corti

the true organ of hearing found in the cochlea.

external ear

the visible part of the ear, not within the structure of the skull.

cilia

tiny hairs along the external auditory canal. aid in transmitting the sound waves inward to other auditory structures

oval window

what separates the middle ear and inner ear.