Senses: Ear & Eye

equilibrium

the sense of balance

gustation

the sense of taste

hearing

the sense or perception of sound

olfaction

the sense of smell

proprioception

the awareness of posture, movement, and changes in equilibrium; receptors are located in muscles, tendons, and joints

sensory receptor

a sensory nerve ending or a specialized structure associated with a sensory nerve that responds to a stimulus

tactile

pertaining to the sense of touch

vision

the sense by which the shape, size, and color of objects are perceived by means of the light they give off

­-esthesia

sensation

­-algesia

pain

­-osmia

sense of smell

­-geusia

sense of taste

cryesthesia

sensitivity to cold

hypalgesia

decreased sensitivity to pain

pseudosmia

false sense of smell

parageusia

abnormal (para­) sense of taste

auditory tube

the tube that connects the middle ear with the nasopharynx and serves to equalize pressure between the outer and middle ear ; pharyngotympanic tube; originally called the eustachian tube

cerumen

the brownish, wax-­like secretion formed in the external ear canal to protect the ear and prevent

infection

cochlea

the coiled portion of the inner ear that contains the receptors for hearing

external auditory canal

tube that extends from the pinna of the ear to the tympanic membrane; external auditory meatus

incus

the middle ossicle of the ear

labyrinth

the inner ear, named for its complex structure, which resembles a maze

malleus

the ossicle of the middle ear that is in contact with the tympanic membrane and the incus

ossicles

the small bones of the middle ear; the malleus, incus, and stapes

pinna

the projecting part of the outer ear; auricle

semicircular canals

the three curved channels of the inner ear that hold receptors for equilibrium

spiral organ

the hearing receptor, which is located in the cochlea of the inner ear; organ of Corti

stapes

the ossicle that is in contact with the inner ear

tympanic membrane

the membrane between the external auditory canal and the middle ear (tympanic cavity); the eardrum; it serves to transmit sound waves to the ossicles of the middle ear

vestibular apparatus

the portion of the inner ear that is concerned with the sense of equilibrium; it consists of the vestibule and the semicircular canals

vestibule

the chamber in the inner ear that holds some of the receptors for equilibrium

vestibulocochlear nerve

the nerve that transmits impulses for hearing and equilibrium from the ear to the brain; eighth cranial nerve; auditory or acoustic nerve

audi/o

hearing

acous, acus, cus

sound, hearing

ot/o

ear

myring/o

tympanic membrane

tympan/o

tympanic cavity (middle ear), tympanic membrane

salping/o

tube, auditory tube

staped/o, stapedi/o

stapes

labyrinth/o

labyrinth (inner ear)

vestibul/o

vestibule, vestibular apparatus

cochle/o

cochlea (of inner ear)

audiology

the study of hearing

acoustic

pertaining to sound or hearing

ototoxic

poisonous or harmful to the ear

myringotome

knife used for surgery on the eardrum

tympanometry

measurement of transmission through the tympanic membrane and middle ear

salpingoscopy

endoscopic examination of the auditory tube

stapedoplasty

plastic repair of the stapes

labyrinthitis

inflammation of the inner ear

vestibulotomy

incision of the vestibule of the inner ear

retrocochlear

behind the cochlea

acoustic neuroma

a tumor of the eighth cranial nerve sheath; although benign, it can press on surrounding tissue and produce symptoms; also called an acoustic or vestibular schwannoma or acoustic neurilemmoma

conductive hearing loss

hearing impairment that results from blockage of sound transmission to the inner ear

Ménière disease

A disease associated with increased fluid pressure in the inner ear and characterized by hearing loss, vertigo, and tinnitus

otitis externa

Inflammation of the external auditory canal; swimmer’s ear

otitis media

inflammation of the middle ear with accumulation of serous (watery) or mucoid fluid

otosclerosis

formation of abnormal and sometimes hardened bony tissue in the ear; it usually occurs around the oval window and the footplate (base) of the stapes, causing immobilization of the stapes and progressive hearing loss

sensorineural hearing loss

Hearing impairment that results from damage to the inner ear, eighth cranial nerve, or auditory pathways in the brain

tinnitus

a sensation of noises, such as ringing or tinkling, in the ear

vertigo

an illusion of movement, as of the body moving in space or the environment moving about the body; usually caused by disturbances in the vestibular apparatus; used loosely to mean dizziness or lightheadedness

myringotomy

surgical incision of the tympanic membrane; performed to drain the middle ear cavity or to insert a tube into the tympanic membrane for drainage

stapedectomy

surgical removal of the stapes; it may be combined with insertion of a prosthesis to correct otosclerosis

aural

pertaining to or perceived by the ear

decibel (dB)

a unit for measuring the relative intensity of sound

hertz (Hz)

a unit for measuring the frequency (pitch) of sound

mastoid process

a small projection of the temporal bone behind the external auditory canal; it consists of loosely arranged bony material and small, air-­filled cavities

stapedius

a small muscle attached to the stapes; it contracts in the presence of a loud sound, producing the acoustic reflex

cholesteatoma

a cyst­like mass containing cholesterol that is most common in the middle ear and mastoid region; a possible complication of chronic middle ear infection

labyrinthitis

inflammation of the ear’s labyrinth (inner ear); otitis interna

mastoiditis

inflammation of the air cells of the mastoid process

presbyacusis

loss of hearing caused by aging

audiometry

measurement of hearing

electronystagmography (ENG)

a method for recording eye movements by means of electrical responses; such movements may reflect vestibular dysfunction

otorhinolaryngology (ORL)

the branch of medicine that deals with diseases of the ear(s), nose, and throat (ENT); also called otolaryngology (OL)

otoscope

instrument for examining the ear

Rinne test

test that measures hearing by comparing results of bone conduction and air conduction; bone conduction is tested through the mastoid process behind the ear

spondee

a two­-syllable word with equal stress on each syllable; used in hearing tests

Weber test

test for hearing loss that uses a vibrating tuning fork placed at the center of the head

accommodation

adjustment of the lens’s curvature to allow for vision at various distances

aqueous humor

fluid that fills the eye anterior to the lens

choroid

the dark, vascular, middle layer of the eye

ciliary body

the muscular portion of the uvea that surrounds the lens and adjusts its shape for near and far vision

cone

a specialized cell in the retina that responds to light; cones have high visual acuity, function in bright light, and respond to colors

conjunctiva

the mucous membrane that lines the eyelids and covers the eyeball’s anterior surface

convergence

coordinated movement of the eyes toward fixation on the same point

cornea

the clear, anterior portion of the sclera

fovea

the tiny depression in the retina that is the point of sharpest vision; fovea centralis, central fovea

iris

the muscular colored ring between the lens and the cornea; regulates the amount of light that enters the eye by altering the size of the pupil at its center

lacrimal gland

a gland above the eye that produces tears

lens

the transparent, biconvex structure in the anterior portion of the eye that refracts light and functions in accommodation

macula

a small spot or colored area; used alone to mean the yellowish spot in the retina that contains the fovea

optic disk

the point where the optic nerve joins the retina; at this point, there are no rods or cones; also called the blind spot or optic papilla

orbit

the bony cavity that contains the eyeball

palpebra

an eyelid; a protective fold (upper or lower) that closes over the anterior surface of the eye

pupil

the opening at the center of the iris

refraction

the bending of light rays as they pass through the eye to focus on a specific point on the retina; also the determination and correction of ocular refractive errors

retina

the innermost, light­-sensitive layer of the eye; contains the rods and cones, the specialized receptor cells for vision

rod

a specialized cell in the retina that responds to light; rods have low visual acuity, function in dim light, and do not respond to color

sclera

the tough, white, fibrous outermost layer of the eye; the white of the eye