Questions and Answers (Graded
A)
photoreceptor - ANSWER - Light-sensitive cells (neurons) in the retina that convert
light energy to neural impulses.
mechanoreceptor - ANSWER - Nerve endings that are sensitive to mechanical
changes in
touch or pressure
glaucoma - ANSWER - An eye disease in which the intraocular pressure is high
enough to cause damage to the optic nerve, resulting in visual loss; caused by
impaired drainage of the aqueous fluid out of the eye
cataract - ANSWER - Clouding of the eye's lens; often congenital or age-related.
macular degeneration - ANSWER - A progressive deterioration of the portion of the
retina called the macula lutea, resulting in loss of central vision
detached retina - ANSWER - Separation of the retina from the choroid in the back of
the
eye; can be caused by injury, tumor, or hemorrhage; causes
"floaters" in the person's vision
iris - ANSWER - A ring of muscle tissue that forms the colored portion of the eye
around the pupil and controls the size of the pupil opening.
retina - ANSWER - Light sensitive layer of the eye; contains rods and cones
, sclera - ANSWER - Known as the white or white of the eye, is the opaque, fibrous,
protective, outer layer of the eye containing collagen and
elastic fiber.
conjuntivitis - ANSWER - inflammation of the membrane that lines the eye,
characterized by red, swollen eyes; pinkeye
conjunctiva - ANSWER - Delicate membrane lining the eyelids and covering the
eyeball
fibrous tunic - ANSWER - First layer of the eyeball that in anterior eye is the cornea,
and posterior eye the sclera "white of the eye"
lens - ANSWER - A transparent disc-shaped structure located behind the iris that can
change its shape, thereby enabling the eye to focus both near and distant objects
on the retina.
optic nerve - ANSWER - Comprised of the axons of retinal ganglion cells, this carries
neural impulses from the eye to the brain.
vitreous humor - ANSWER - jellylike substance found behind the lens in the posterior
cavity of the eye that maintains its shape
blind spot - ANSWER - The point at which the optic nerve leaves the eye, creating a
"blind" spot because no receptor cells are located there
pupil - ANSWER - A hole in the center of the iris of the eye that allows light to enter
the eyeball. The diameter of pupil is controlled by the iris in response to the
brightness of the light.
tapetum - ANSWER - Iridescent layer found in nocturnal animals for maximizing
vision under low intensity light; Reflective layer of tissue located beneath
photoreceptors enhances the amount of light available under low light conditions