CH 17 DEFINITIONS EYE EAR Flashcards
normal adjustmentof the eye to focus on objects from far to near. when this occurs, the ciliary body adjusts the lens, rounding it, and the pupil constricts. when the eye focuses from near to far, the ciliary body ff;attens the ;ens and thepupil dilates.
accomodation
area behind the cornea and in front of the lens and iris. it contains aqueous humor.
anterior chamber
fluid produced by the ciliary body and found in the anterior chamber. a humor (latin humidus means moist) is any body fluid, including blood and lymph
aqueous humor
consisting of two surfaces that are rounded, elevated, and curved evenly, like part of a sphere. the lens of the eye is a biconvex body.
biconvex
middle, vascular layer of the eye, between the retina and the sclera
choroid
structure surrounding the lens that connects the iris to the choriod. it contains ciliary muscles, which control the shape of the lens, and it secretes aqueous humor.
ciliary body
photoreceptor cell in the retina that transforms light energy into a nerve impulse. cones are responsible for color and central vision.
cone
delicate membrane lining the eyelids and covering the eyball up to the cornea.
conjunctiva
fibrous transparent layer of clear tissue that extends over the anterior portion of the eyeball. derived from latin corneus, meaning horny, perhaps because as it protrudes outward, it was thought to resemble a horn
cornea
tiny pit or depression in the retina that is the region of clearest vision
fovea centralis
posterior, inner part of the eye; visualized with an opthalmoscope
fundus of the eye
pigmented, colored layer that opens and closes to allow more or less light into the eyes
iris
transparent, biconvex body behind the pupil of the eye; it bends/refracts light rays to bring them into focus on the retina
lens
small oval region on the retina near the optic disc, contains the fovea centralis, which is the area of clearest vision
macula
point at which optic nerve fibers cross in the brain- chiasma means crossing in latin
optic chiasm
region at the back of the eye where the optic nerve meets the retina. it is the blind spot of the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive to light
optic disc
cranial nerve carrying impulses from the retina to the brain (cerebral cortex)
optic nerve
central opening of the eye, surrounded by the iris, through which light rays pass. it appears dark.
pupil
bending of light rays by the cornea, lens, and fluids of the eye to bring the rays into focus on the retina. refract means to “break back”
refraction
light sensitive nerve cell layer of the eye containing photo receptor cells, rods and cones
retina
photoreceptor cell of the retina essential for vision in low light and for peripheral vision
rod
tough white outer coat of the eyeball
sclera
relay center of the brain. optic nerve fibers pass through the thalamus on their way to the cerebral cortex.
thalamus
soft jelly like material behind the lens in the vitreous chamber; helps maintain the shape of the eyeball. often referred to as the vitreous.
vitreous humor
fluid in the anterior chamber of the eye
aqueous humor
blepharitis
inflammation of the eyelid
drooping eyelid- may be caused by abnormalities of the eyelid muscle or by nerve damage
blepharoptosis
inflammation of the conjunctiva- commonly called pinkeye, occurs when blood vessels dilate from allergens like pollen in allergic coonjunctivits, bacterial infection or viral infection
conjunctivitis
unequal pupil size- may be an indication of neurological injury or disease
anisocoria
scratch on cornea
corneal abrasion
paralysis of the ciliary muscles of the eye
cycloplegic
inflammation of the tear glands
dacryoadenitis
inflammation of the iris- charecterized by pain, sensitivity to light, and lacrimation. a corticosteroid is prescribed to reduce inflammation.
iritis
pertaining to the iris
iridic
removal of the iris, partial or full- may be removed to improve drainage of aqueous humor or to extract a foreign body
iridectomy
inflammation of the cornea
keratitis
pertaining to tears
lacrimal
production of tears
lacrimation
pertaining to within the eye
intraocular
medical doctor who specializes in treating disoders of the eye
opthalmologist
pertaining to the eye
opthalmic
paralysis of the muscles that move the eye
opthalmoplegia
pertaining to eye/vision
optic
nonmedical professional who can examine eyes to determine vision problems and prescribe lenses; a doctor of optometry
optometrist
nonmedical professional who grinds lenses and fits glasses but cannot prescribe lenses
optician
pertaining to eyelid
palpebral
swelling of the optic disc. this condition is associated with intracranial pressure and hyperemia/increased blood flow in the region of the optic disc
papilledema
cataract removal surgery- technique of cataract extraction using ultrasonic vibrations to fragment/emulsify the lens and aspirate pieces from the eye
phacoemulsification