The Special Senses
Eye and Ear
Lecture 10
The special senses of the eyes and ears
are SENSORY input devices. The eyes and
ears detect sensory information from the
environment. They are responsible for
sending this input to the brain for
interpretation.
 The special senses DO NOT interpret the
stimuli.
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Some definitions
Stimulus
- change in the environment
Receptor
- device to detect a stimulus
Response
- the interpretation of the stimulus causing
some action from the body
Anatomy
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Sclera = outer protective layer of the eye white portion.
Cornea = transparent anterior part of the sclera,.
Choroid = middle layer of the eye.
Iris = muscular structure that give the eye its color,
allows light to pass through.
Pupil = opening in the center of the iris.
Lens = behind the pupil, focus and bend light.
Retina = innermost layer, contains the vision receptors.
The eye
Anatomy
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Aqueous fluid = watery liquid found in the
anterior cavity of the eye.
Vitreous fluid = jelly like fluid found behind the
lens in the posterior cavity of the eye.
Lacrimal glands & ducts = produce and drain
tears.
Optic nerve = carries visual impulses from the
retina to the brain.
Conjunctiva = mucous membrane lining the
eyelids and anterior portion of the sclera.
Section through the eye
The Eye
Blephar/o
Choroid/o
Corne/o
Kerat/o
Dacry/o lacrim/o
Dipl/o
Irid/o iri/o
Conjunctiv/o
Cur/o core/o pupill/o
eyelid
choroid
cornea
tear, tear duct.
double
iris
conjunctiva.
pupil
Ophthalm/o ocul/o
Opt/o
Retin/o
Scler/o
Cry/o
Phot/o
Ton/o
eye
vision
retina
sclera
cold
light
tension, pressure.
New Suffixes
-spasm
twitching
e.g., blepharospasm
-opia
vision
e.g., diplopia
-plegia
paralysis
e.g., iridoplegia
- Bi- bin-
two.
-ician
one who.
-phobia
abnormal fear of or aversion to
An OPHTHALMOSCOPE is a device to
examine the interior of the eye
High Blood Pressure (HTN) may cause
OPHTHALMODYNIA (pain in the eye)
A swelling of the eyelid is called
BLEPHAREDEMA
Plastic surgery of the eye to remove
wrinkles is called an eye tuck or
BLEPHAROPLASTY
Dirty contact lenses can cause a severe
infection called KERATITIS.
 Rupture of the cornea is known as
KERATORRHEXIS. The cornea is incised
with an instrument known as a
KERATOTOME.
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A laser KERATOTOMY is a procedure that can
eliminate the need for eyeglasses.
 MYOPIA (nearsightedness) is a condition where
the stimulus image falls in front of the retina.
 The opposite of myopia is farsightedness or
HYPEROPIA where the image falls behind the
retina.
 Both myopia and hyperopia can be corrected
with glasses.
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The eyelids protect the eyes, shade eyes during
sleep, and spread lubricating fluid.
 This lubricating fluid come from three areas:
LACRIMAL GLANDS located above the outer
corner of each eye, LACRIMAL DUCTS which
drain gland secretions into the lacrimal sacs.
 The term DACRY/O is used to denote tears.
 The word DACRYADENALGIA means
pain in a tear gland
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Disease & Disorder Terms
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Blepharitis = inflammation of the eyelid.
Blepharoptosis = drooping of the eyelid.
Conjunctivitis = inflammation of the conjunctiva.
Dacryocystitis = inflammation of the tear sac.
Diplopia = double vision.
Iridoplegia = paralysis of the iris.
Keratitis = inflammation of the cornea.
Ophthalmalgia = pain in the eye.
Ophthalmorrhagia = rabid flow of blood from the eye.
Disease & Disorder Terms
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Photophobia = fear of, sensitivity to light.
Retinoblastoma = tumor arising from the
developing retinal cell.
Sclerokeratitis = inflammation of the sclera and
cornea.
Scleromalcia = softening of the sclera.
Astigmatism = defective curvature of the
refractive surface of the eye.
Cataract = clouding of the lens of the eye.
Glaucoma = increased intraocular tension.
Disease & Disorder Terms
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Hyperopia = farsightedness.
Myopia = nearsightedness.
Nyctalopia = poor vision at night.
Nystagmus = involuntary, rhythmic movements
of the eye.
Retinitis pigmentosa = hereditary progressive
disease marked by night blindness with atrophy
and retinal pigment changes.
Strabismus = squint or crossed eyes.
Sty = an acute infection of the secretory glands
of the eyelids.
Surgical Terms
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Blepharoplasty = surgical repair of the eyelid.
Dacryocystotomy = incision into the tear sac.
Iridectomy = excision of part of the iris.
Keratoplasty = surgical repair of the cornea.
Cryoextraction of the lens = cataract is lifted from the
eye with an extremely cold probe.
Enucleation = removal of the eye.
Vitrectomy = removal of all or part of the vitreous fluid.
Surgical Terms
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Redial keratotomy = spoke like incisions are made to
flatten the cornea, correctingn nearsightedness
(myopia).
Strabotomy = incision into the tendon of an extrinsic
muscle to relieve strabismus.
Fluorescein Angiography = x-ray filming of the blood
vessels using fluorescing dye.
Keratometer = used to measure the curvature of the
cornea.
Ophthalmoscope = used for visual examination of the
eye.
Procedural Terms for the EYE
Optometer = used to measure vision,
power and range.
 Pupillometer = used to measure width and
diameter of the pupil.
 Tonometer = used to measure pressure
within the eye, used to diagnose
glaucoma.
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Complementary Terms
Binocular = pertaining to both eyes.
Intraocular = pertaining to within the eye.
Lacrimal = pertaining to tears or tear duct.
Ophthalmic = pertaining to the eye.
Ophthalmologist = physician who specializes in
ophthalmology.
 Optic = pertaining to vision.
 Optician = one who is skilled in filling prescription for
lenses.
 Retinopathy = noninflammatory disease of the retina.
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Complementary Terms
Miotic = agent that constricts the pupil.
Mydriatic = agent that dilates the pupil.
Oculus dexter = OD, right eye.
Oculus sinister = OS, left eye.
Oculus uterque = OU, each eye.
Optometrist = health professional who
prescribes corrective lenses.
 Visual acuity = VA, sharpness of vision of either
distance or nearness.
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The Ear
The ear has three divisions:
outer ear (external ear)
middle ear
inner ear
 The outer ear takes sound waves and directs
them into the ear canal.
 The middle ear takes those sound waves and
converts them to electrical energy.
 The inner ear takes that electrical energy and
transmits it to the brain. It also is responsible
for balance.
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The external ear contains the AURICLE.
This structure is the earlobe (PINNA) that
directs sound into the auditory canal. At
the end of the auditory canal, you find a
thin membranous sheet called the
TYMPANIC MEMBRANE (eardrum).
Vibrations of the eardrum cause a mechanical
vibration of the three middle ear bones. The
MALLEUS (hammer), INCUS, and STAPES. Each
of these bones are connected. The malleus is
connected to the tympanic membrane.
 Once the vibration is detected at the last bone
(STAPES), the stapes cause a vibration at the
opening of the inner ear, OVAL WINDOW.
 The middle ear is connected to the throat by the
EUSTACIAN TUBE.
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The inner ear includes the COCHLEA and
SEMICIRCULAR CANALS.
 The cochlea is filled with fluid and small hair
cells that detect minute vibrations. These
vibrations are interpreted by the brain via the
AUDITORY NERVE.
 The SEMICIRCULAR CANALS are also filled with
fluid. Sudden movements of the head cause this
fluid to move. This eventually causes dizziness
(vertigo).
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Anatomy
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Auricle, pinna = bilateral of the head, directs sound
waves in the external auditory meatus.
External auditory meatus = short tube ends at the
tympanic membrane.
Tympanic membrane = eardrum semitransparent
membrane that separates the external meatus and the
middle ear cavity.
Eustachian tube = connects the middle ear and the
pharynx (throat). Regulates air pressure.
Ossicles = bones of the middle ear, carry sound
vibrations, malleus (hammer), incus (anvil), stapes
(stirrup).
Anatomy
Inner ear Labyrinth = bony spaces within the temporal
bone of the skull.
 Cochlea =snail shaped and contains the organ of
hearing.
 Semicircular canals & vestibule = contains receptors and
endolymph that help the body maintain its balance or
equilibrium.
 Mastoid bone and cells = located in the skull bone
behind the external auditory meatus.
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Combining Forms for the EAR
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Acou/o audi/o = hearing
Aur/i aur/o = ear.
Labyrinth/o = labyrinth.
Mastoid/o = mastoid bone.
Myring/o = tympanic membrane (eardrum).
Ot/o = ear.
Staped/o = stapes (middle ear bone).
Tympan/o = tympanic membrane, eardrum.
Salping/o
eustachian tube
Disease and Disorder Terms
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Labyrinthitis = inflammation of the labyrinth.
Mastoiditis = inflammation of the mastoid bone.
Myringitis = inflammation of the eardrum.
Otalgia = pain in the ear.
Otomycosis = fungus in the ear.
Otopyorrhea = discharge of pus from the ear.
Tympanitis = inflammation of the middle ear.
Otitis Meida.
Ceruminoma = tumor of the glands that secrete earwax.
Disease and Disorder Terms
Otitis externa = inflammation of the outer ear.
 Otitis media = inflammation of the middle ear.
 Tinnitus = ringing in the ears.
 Vertigo= dizziness.
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Surgical Terms
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Labyrinthectomy = excision of the labyrinth.
Mastoidectomy = excision of the mastoid bone.
Myringoplasty = surgical repair of the tympanic
membrane.
Myringotomy = incision of the tympanic membrane,
performed to release pus and relieve pressure in the
middle ear.
Tympanoplasty = surgical repair of the eardrum.
Procedural Terms
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Acoumeter = instrument used to measure,
acuteness of hearing.
Audiogram = graphic record of hearing.
Audiometry = measurement of hearing.
Otoscopy = visual examination of the ear.
Tympanometer = instrument to measure middle
ear functions.
Complementary Terms
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Audiologist = one who is skilled in and
specializes in audiology.
Audiology = study of hearing.
Otologist = physician who studies and treats
diseases of the ear.
Otology = study of the ear.
Otorhinolaryngologist = ENT physician who
studies and treats diseases and disorders of the
ear, (ear, nose, & throat).