Week #6 Eye - Internal Anatomy

Iris

• Colored portion of the eye

• Pigmented, muscular diaphragm that controls the amount of light that enters the posterior part of the globe

Pupil

• Opening in the center of the iris

Lens

• The lens is a soft, transparent structure made up of microscopic fibers that are arranged like the layers of an onion

• Elastic and biconvex

• Focus

• The process where the shape of the lens is changed by the ciliary body is called accommodation

Ciliary Body

• Contains ciliary muscles that adjust the shape of the lens
• Located immediately behind the iris

• Located in the middle, vascular layer of the eye

Retina

• Complex, multilayer structure that lines most of the vitreous compartment

• This is where the visual image is formed, sensed, and converted to nerve impulses that are transmitted up the optic nerve to the occipital lobe

• The rest of the eye exists to support the retina

Tapetum

• Sandwiched between the sclera and retina

• Mostly made of pigment and blood vessels that supply the retina

• Forms the tapetum lucidum, which is a highly reflective area in the rear of the eye

• Acts as a light amplifier to aid in low-light vision