Biology 30: Nervous System: Eye Functions

Sclera

Outer white layer of eye; gives shape and serves as attachment site for muscles.

Cornea

Transparent part of sclera; refracts entering light toward the pupil.

Choroid Layer

Middle layer containing blood vessels supplying nutrients/O2; dark pigment absorbs light.

Retina

Inner layer containing photoreceptors (rods and cones) for vision.

Rods

Photoreceptors specialized for vision in dim light and shades of grey.

Cones

Photoreceptors specialized for color vision and sharp detail in bright light.

Fovea

Area of sharpest vision containing high concentration of cones.

Blind Spot

Location of optic nerve attachment; contains no rods or cones.

Optic Nerve

Transmits visual sensory information to the occipital lobe of the brain.

Iris

Colored part of eye; regulates amount of light entering pupil.

Pupil

Opening in center of iris that allows light to enter inner eye.

Lens

Focuses incoming images onto retina.

Aqueous Humor

Watery liquid that protects lens and supplies cornea with nutrients.

Vitreous Humor

Cloudy, jelly-like material filling eyeball to maintain its shape.

Ciliary Muscles

attached to lens, helps with movement