Chapter 17 Eye Flashcards
pupil
central dark opening of the eye
iris
colored portion of the eye
conjunctiva
membrane lining the inner surfaces of the eyelids
cornea
fibrous, transparent tissue that extends like a dome over pupil and iris
refraction
bending of light rays by the cornea
sclera
opaque white of the eye
choroid
dark brown membrane inside sclera
accomodation
normal adjustment of the eye to focus on objects from near to far
anterior chamber
area behind the cornea and in front of the lens and iris
aqueous humor
fluid produced by the ciliary body and found in the anterior chamber
biconvex
consisting of two surfaces that are rounded, elevated, and curved evenly like a sphere.
ciliary body
structure surrounding the lens that connects the iris to the choroid
cone
photoreceptor cell in the retina that transforms light energy into a nerve impulse
- responsible for color and central vision
fovea centralis
tiny pit or depression in the retina that the region clearest vision
fundus of the eye
posterior, inner portion of the eye
- visualized with a opthalmoscope
lens
small transparent, biconvex body behind the pupil of the eye
- it bends light rays to bring them into focus on the retina
macula
small oval region on the retina near the optic disc
- contains fovea centralis
optic chiasm
point at which optic nerves 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 in the eye due to lack of rods and cones (only nerve fibers)
optic nerve
cranial nerve carrying impulses from retina to the brain
rod
photoreceptor cell of the retina for vision in low light and for peripheral vision
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 eye
astigmatism
defective curvature of the cornea or lens of the eye
hyperopia
hypermetropia
farsightedness
myopia
nearsightedness