Ch17 Vocab. & Abbrev. Flashcards
(69 cards)
accommodation
normal adjustment of 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 flattens the lens and the pupil dilates.
anterior chamber
area behind the cornea and in front of the lens and iris.
Contains aqueous humor
aqueous humor
fluid produced by the ciliary body and found in the anterior chamberr.
A humor is any body fluid, including blood and lymph.
biconvex
consisting of two surfaces that are rounded, elevated, and curved evenly, like part of a sphere.
The lens of an eye is a biconvex body.
choroid
middle, vascular layer of the eye, between the retina and the sclera.
ciliary body
structure surrounding the lens that connects the iris to the choroid.
It secretes aqueous humor.
cone
photoreceptor cell in the retina that transforms light energy into a nerve impulse.
Cones are responsible for color and the central vision
conjunctiva
delicate membrane lining the eyelids and covering the eyeball up to the cornea
cornea
fibrous transparent layer of clear tissue that extends over the anterior portion of the eyeball.
Protrudes outward, it was thought to resemble a horn
fovea centralis
tiny pit or depression in the retina that is the region of clearest vision
fundus of the eye
posterior, inner part of the eye;
visualized with an ophthalmoscope
iris
pigmented (colored) layer that opens and closes to allow more or less light into the eye.
The central opening of the iris is the pupil.
lens
transparent, biconvex body behind the pupil of the eye.
It bends (retracts) light rays to bring them into focus on the retina.
macula
small oval region on the retina near 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 chiasm
point at which optic nerve fibers cross in the brain
optic disc
region at the back of the eye where the optic nerve meets the retina.
It is the blind spot oof the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive to light.
optic nerve
cranial nerve carrying impulses from the retina to the brain (cerebral cortex)
pupil
central opening of the eye, surrounded by the iris, through which light rays pass.
It appears dark.
refraction
bending of light rays by the cornea, lens, and fluids of the eye to bring the rays into focus on the retina.
Refract means break (-fract) back (re-)
retina
light-sensitive nerve cell layer of the eye containing photoreceptor cells (rods and cones)
rod
photoreceptor cell of the retina essential for vision in low light and for peripheral vision
sclera
tough, white outer coat of the eyeball
thalamus
relay center of the brain.
Optic nerve fibers pass through the thalamus on their way to the cerebral cortex
vitreous humor
soft, jelly-like material behind the lens in the vitreous chamber;
helps maintain the shape of the eyeball. often referred to as the vitreous
