Chapter 17 Vocab For Eyes

Front 1

accommodation

Back 1

Normal adjustment of the eye to focus on objects from far to near. The ciliary body adjusts the lens (rounding it) and the pupil constricts. When the eye disaccommodates, it focuses from near to far. The ciliary body flattens the lens and the pupil dilates.

Front 2

anterior chamber

Back 2

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

Front 3

aqueous humor

Back 3

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.

Front 4

biconvex

Back 4

Having two sides that are rounded, elevated, and curved evenly, like part of a sphere. The lens of the eye is a biconvex body.

Front 5

choroid

Back 5

Middle, vascular layer of the eye, between the retina and the sclera.

Front 6

ciliary body

Back 6

Structure on each side of the lens that connects the choroid and iris. It contains ciliary muscles, which control the shape of the lens, and it secretes aqueous humor.

Front 7

cone

Back 7

Photoreceptor cell in the retina that transforms light energy into a nerve impulse. Cones are responsible for color and central vision.

Front 8

conjunctiva

Back 8

Delicate membrane lining the eyelids and covering the anterior eyeball.

Front 9

cornea

Back 9

Fibrous transparent layer of clear tissue that extends over the anterior portion of the eyeball. Derived from the Latin corneus, meaning horny, perhaps because as it protrudes outward, it was thought to resemble a horn.

Front 10

fovea centralis

Back 10

Tiny pit or depression in the retina that is the region of clearest vision.

Front 11

fundus of the eye

Back 11

Posterior, inner part of the eye.

Front 12

iris

Back 12

Colored pigmented membrane surrounding the pupil of the eye.

Front 13

lens

Back 13

Transparent, biconvex body behind the pupil of the eye. It bends (refracts) light rays to bring them into focus on the retina.

Front 14

macula

Back 14

Yellowish region on the retina lateral to and slightly below the optic disc; contains the fovea centralis, which is the area of clearest vision.

Front 15

optic chiasm

Back 15

Point at which optic nerve fibers cross in the brain (chiasm means crossing).

Front 16

optic disc

Back 16

Region at the back of the eye where the optic nerve meets the retina. It is the lind spot of the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive to light.

Front 17

optic nerve

Back 17

Cranial nerve carrying impulses from the retina to the brain (cerebral cortex).

Front 18

pupil

Back 18

Dark opening of the eye, surrounded by the iris, through which light rays pass.

Front 19

refraction

Back 19

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 (-fract) back )(re-)

Front 20

retina

Back 20

Light-sensitive nerve cell layer of the eye containing photoreceptor cells (rods and cones).

Front 21

rod

Back 21

Photoreceptor cells of the retina essential for vision in dim light and for peripheral vision.

Front 22

sclera

Back 22

Tough, white outer coat of the eyeball.

Front 23

thalamus

Back 23

Relay center of the brain. Optic nerve fibers pass through the thalamus on their way to the cerebral cortex.

Front 24

vitreous humor

Back 24

Soft, jelly-like material behind the lens in the vitreous chamber; helps maintain the shape of the eyeball.