Eye, Ear, and Special Senses

Receptors

sensory nerve endings, cells, or sense organs that produce afferent‐sensory impulses to the brain

exteroceptors

The receptors of the five senses

interoceptors

respond to internal stimuli of the body

photoreceptors

respond to light

chemoreceptors

respond to chemicals

tactile receptors

respond to touch

auditory receptors

respond to sound

Adnexa

used in anatomical terminology for accessory structures to an organ

Eyelid

the moveable protective folds that cover the eye

Blepharon or palpebra

loan word for eyelid

Conjunctiva

The mucous membrane that lines the eyelids and reflects back onto the eyeball

Lacrimal Apparatus

tear; anatomical structures associated with tears

Eye

the organ of sight

Iris

The colorful circle of the human eye

Pupil

The hole in the iris by which light enters the eye

Ciliary body

a ring of tissue behind the iris that is composed of ciliary muscle and ciliary processes

Sclera

white of the eyes

Choroid

the middle vascular layer of the eyeball

retina

the innermost layer of the eye that contains the photoceptors known as the rod and cone cells, which are highly specialized, light‐sensitive cells

Cornea

The transparent anterior continuation of the sclera that is convex anteriorly

anterior camera

the space between the lens and the cornea

posterior camera

lies between the iris and the lens

Lens

transparent structure that light comes through once refracted by the cornea

Vitreous humor

focused light travels through here

Macula lutea

central yellow spot on the posterior wall of the retina, where light that has been refracted by the cornea and lens comes to a focal point

Vision

sense of sight

parablepsis

abnormality of vision, such as hallucinations,

Amblyopia

dull vision; a unilateral or bilateral decrease of best corrected vision in an otherwise healthy eye

Presbyopia

presbyopia is the permanent loss of accommodation of the crystalline lens of the eye that occurs when people are in their 40s

Asthenopia

weak vision; weakness or tiring of the eyes

Photopia

light vision;  the adjustment of the eye for vision in bright light

Scotopia

dark vision; adjustment of the eye for vision in dim light

Diplopia

double vision; two images of an object seen at the same time

Anisopia

unequal vision; condition where visual power of the eyes is unequal

Scotoma

A dark spot or an area of diminished acuity in the visual field

Anopia

bindness or lack of vision

hemianopia

blindness in one‐half field of vision

protanopia

a lack of “primary” vision (red color blindness)

deuteranopia

a lack of “secondary” vision (green color blindness)

nyctalopia

night blindness

Refractive error

due to the light refractive powers of the eye not being appropriate for clear vision

ametropia

refreactive errors of vision; “disproportionate” or “lack of measure” vision

Hyperopia

farsightedness; a type of refractive error that allows one to see at a distance but not close up

Myopia

nearsightedness; a type of refractive error that allows one to see close up but not at a distance

Astigmatism

The form of ametropia in which the refraction of rays is spread over a wide area rather than coming to focal point on the retina

Cataract

he opacity of a lens leading to a loss of vision and photophobia (an aversion to bright light)

Glaucoma

an intraocular disease of the eye characterized by increased intraocular pressure due to the overaccumulation of the aqueous humor

Strabismus or heterotropia

disorders of the eye in which the optic axes cannot be directed to the same object

esotropia

inward deviation of the eye

exotropia

outward deviation of the eye

Nystagmus

involuntary back‐and‐forth movement of the eyes

iridoplegia

Paralysis of the sphincter muscles of the iris resulting in a dilated pupil

cycloplegia

paralysis of the ciliary body resulting in a loss of accommodation

ophthalmoplegia

Paralysis of the ocular muscles that move the eyeball

Ophthalmia

severe inflammation of the eye

Endophthalmitis

an inflammation of the internal eye that may occur in the anterior or posterior camera of the eye

Exophthalmos (or exophthalmia)

an abnormal anterior protrusion of the eyeball

Scleritis

an inflammation of the sclera

Conjunctivitis

an inflammation of the conjunctiva; pink eye

Trachoma

a chronic conjunctivitis caused by the bacteria Chlamydia trachomatis

Pterygium

a triangular or “wing‐like” thickening of the conjunctiva extending onto the eye

Keratitis

an inflammation of the cornea

Keratorrhexis

a rupture of the cornea

Keratocele

a corneal protrusion

Keratoncus

a type of hereditary corneal dystrophy resulting in a conical protrusion of the central part of the cornea

Keratoconjunctivitis sicca

dry eye syndrome

Iritis

an inflammation of the iris

Aniridia

the absence of all or part of the iris

Heterochromia iridis

congenital disorder in which one iris is a different color than the other iris in an individual

Corectopia

a congenital defect where the pupil is not in its normal position

Miosis

condition in which the pupil is smaller or lessened

Mydriasis

a condition in which the pupil is enlarged or dilated

Retinitis

an inflammation of the retina of the eye

Photoretinitis

an inflammation of the retina caused by bright light

Retinoschisis

the pathological splitting of the retina

Maculopathy

a term for a collection of retinal pathologies affecting the macula of the eye

Ectropion

An outward turning of an eyelid

Entropion

An inward turning of an eyelid

Trichiasis

a condition in which an eyelash rubs on the conjunctiva or the cornea

Blepharitis

Inflammation of an eyelid

Blepharochalasis

The loss of elasticity of the skin of the upper eyelid with old age that causes it to become slack

Blepharoptosis

a drooping or downward displacement of an eyelid

Hordeolum

the technical term for a stye

Chalazion

a swelling in the middle part of the eyelid that is formed by a distention of a meibomian gland

Dacryoadenitis

an inflammation of the lacrimal gland

Dacryocystitis

inflammation of the tear sac

Epiphora

an abnormal excessive flow of tears

Auricle

conspicuous “ear flap” at the side of the head; part of the auris externa

Auditory meatus

external auditory canal

meatus

The external opening of the auditory canal

tympanum or myringa 

eardrum

Ossicles

the auditroy bones that make up the ear drum

Eustachian Tube

regulates air in middle ear to fix for atmospheric pressure

Oval window

fenestra vestibuli; transmits vibrations to the cochlea for hearing

Vestibule

connects the cochlea and semicircular canals and assists in their function

utricle

larger sack of the vestibule

saccule

smaller sack of the vestibule

Cochlea

The spiral snail‐shaped portion of the inner ear responsible for hearing

Hearing

sense of hearing

Presbyacusis

A hearing impairment of old age