The Nervous System

Cornea [description]

Transparent coating on the front of the eye

Cornea [function]

Protects the eye, refracts light entering the eye

Pupil [description]

Central hole in the iris

Pupil [function]

Allows light to enter the eye

Iris [description]

Coloured ring of muscle tissue

Iris [function]

Alters pupil size by contracting or relaxing

Lens [description]

Transparent biconcave lens

Lens [function]

Focuses light clearly onto the retina

Ciliary body [description]

Ring of muscle tissue

Ciliary body [function]

Alters shape of lens

Suspensory ligaments [description]

Ligament tissue

Suspensory ligaments [function]

Connects ciliary muscle to the lens

Optic nerve [description]

Nervous tissue

Optic nerve [function]

Carries nerve impulses to brain

Focusing on distant object

Ciliary muscles relax, suspensory ligaments pulled tight, lens pulled thin

Focusing on a nearby object

Ciliary muscles contract, suspensory ligaments slackened, lens allowed to bulge