chapter 14: special sense organs of the peripheral nervous system

Choroid/o

choroid

Chrom/o

color

Receptors

Sensory nerve endings that respond to various kinds of stimulation

Corne/o, kerat/o

cornea

dacry/o, lacrim/o

tear

ir/o, irid/o

iris

ocul/o, ophthalm/o

eye

opt/o, optic/o

vision

presby/o

old or old age

pupil/o

pupil

Conjuctiv/o

conjunctiva

ton/o

tone or tension

acoust/o, audi/o

hearing

adenoid/o

adenoids

aur/o, auricul/o, ot/o

ear

cerumin/o

ear wax

cochle/o

cochlea

myring/o, tympan/o

eardrum

salping/o

eustachian tube

-ory

pertaining to

chem/o

chemical

mechan/o

mechanical

noc/i

cause harm, injury, or pain

phot/o

light

therm/o

heat

-osmia

sense of smell

retin/o

retina

Sense Organs

eyes, ears, skin, mouth, and nose

Pupil

The small dark circular structure in the center of the eye which is surrounded by the colored portion of the eye that we regularly see

Iris

Colored part of the eye

Sclera

tough outer layer of eye; white opaque membrane covering most of the eyeball

Conjunctiva

Mucous membrane lining the inner surface of the eyelid and acts as a protective covering for the exposeed surface of the eye

Lacrimal glands

Produce and store tears

Lacrimal fluid

tears

Lacrimal Ducts

channels that carry tears to the eye that drain into the large nasolacrimal sac

Nasolacrimal sac

large sac in which tears drain after passing through the lacrimal ducts

Nasolacrimal Duct

A duct that carries tears from the lacrimal sac to the nasal cavity

Tearing

Process when a person is crying

Cornea

Transparent structure at the front of the eyeball that bends or refracts light rays so they are focused properly on the sensitive receptor cells in the posterior

Choroid

Dark brown membrane inside the sclera

Ciliary Body

Located on the anterior surface of the eye

Lens

A clear piece of curved glass or plastic that bends passing light to focus or spread the light rays

Refraction

The bending of a wave as it passes at an angle from one medium to another

Accommodation

Refractory adjustment for close vision

Anterior Chamber

Area behind the cornea and in front of the lens and iris. It contains aqueous humor.

Vitreous Chamber

Filled with vitreous humor

Vitreous humor

Soft, jell-like material found in the vitreous chamber

Retina

Delicate nervous tissue membrane of the eye

Optic nerve

nerve that enables vision

Optic disc

Region of the eye where the optic nerve meets the retina; no light receptors present

Rods and Cones

sensitive receptor cells of the retina; rods responsible for peripheral vision, night vision, and detection of motion; cones function is color and central vision

Daltonism

unable to distinguish greens from reds

Achromatic Vision

a defect in the retinal cones in which the person cannot distinguish any color

Snellen Chart

Eye chart used by eye care professionals and others to measure visual acuity. Named after Hermann Snellen, a Dutch ophthalmologist.

Conjunctival

Pertaining to the Conjuctiva

Choroidal

Pertaining to the choroid

Corneal

Pertaining to the cornea

Iridic

Pertaining to the iris

Lacrimal

Pertaining to the tears

Ocular

Eye

Optic

Pertaining to the eye

Ophthalmic

pertaining to the eye

Pupillary

Pertaining to the pupil

Retinal

Pertaining to the retina

Myopia

nearsightedness

Hyperopia

farsightedness

Astigmatism

Uneven focusing of the image, resulting from distortion of the curvature of the lens or cornea

Tonometry

Measuring of intraocular pressure using a tonometer

Assessment of visual fields

Determines the physical space visible to an individual in a fixed position

Mydiatric

agent that dilates the pupil

Presbyopia

Hyperopia and impairment of vision due to advancing years of old age

Accommodation reflex

Ability of the eye to adjust to variations in distance

Fluorescein Angiography

Uses fluorescein to examine movement of blood through blood vessels in the eye

Amblyopia

Reduced vision in one eye, not correctable by glasses but by wearing eye patch

Strabismus

A disorder in which the eyes point in different directions or are not aligned correctly because the eye muscles are unable to focus together

Blepharitis

Inflammation of the eyelid

Cataract

An abnormal progressive condition of the lens, characterized by loss of transparency

Color Vision Deficiencies

Achromatic vision, Achromatopsia, Daltonism

Achromatopsia

Profound inability to see color

Conjunctivitis

Inflammation of the conjunctiva; red eyes or pink eye

Glaucoma

Abnormal condition of increased pressure within the eye

Hordeolum

sty or stye, resulting from an infected sebaceous gland of an eyelash

Macular degeneration

A progressive deterioration of the retina associated with new vessel formation that can progress to blindness

Nyctalopia

Poor vision at night or in dimlight

Photophobia

Excessive sensitivity of the eyes to light

Ptosis

Drooping of the upper eyelids

Retinal Detachment

Separation of the retina from the choroid, resulting from a hole or tear in the retina

Retinopathy

Any disease of the retina

Iridectomy

surgical removal of part of the iris

Blepharoplasty

surgical repair of the eyelid to repair ptosis

Corneal Transplant

Transplantation of corneal tissue from a donor or the patient's own cinema

Ophthalmic cryosurgery

term for the use of extreme cold to remove a cataract or to cause the edges of a detached retina to heal

Cryoextraction

Removal of a cataract using an extremely cold probe

Corneal abrasion

scraping away of the outer layers of the cornea

Extraction of the lens

removal of the lens to treat a cataract

Intraocular lens transplant

Replacing the lens with an artificial lens

Laser Retinal Photocoagulation

Uses laser to make pinpoint scars to stabilize a detached retina

LASIK

corneal surgery in which the excimer laser and a microkeratome are combined to correct nearsightedness

Cerumen

Lubricates and protects the ear

Tympanic membrane

eardrum