Communication-Refraction in relation to the human eye

Essay by slayerccHigh School, 12th grade July 2004

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1. Describe the anatomy and function of the human eye.

Conjunctiva- a delicate membrane that covers the surface of the

eye and the inside of eyelids.

Protects the front of the eye.

Cornea- The front part of the eyeball. It is transparent, relatively

thick. Bends light rays as they pass through it.

Sclera- Continuous with the cornea but not transparent. Forms

tough white outer back part of eyeball. Protects the eye, helps maintain

it's shape.

Choroid- lies on the inside of sclera, think black pigmented layer

containing blood vessels. Pigment absorbs stray light preventing false


Retina- Innermost layer of eye. Lines back of eyeball, contains

light sensitive cells or photoreceptors and nerve fibres. Receives the light

and changes it in to electrical impulses that travel to the brain via the optic


Iris- coloured part at front of eye, composed of muscles.

Regulates the amount of light entering the eye.

Lens- transparent biconvex protein disc behind the pupil. Focuses

light rays on to the retina.

Aqueous humor and Vitreous humor- aqueous humor is viscose

liquid that fills the front chamber of the eye. Vitreous humor is jelly-like

and fills the larger back chamber of the eye. Help keep the eyeball in

shape and also bend rays of light as they pass through.

Ciliary body- connects the choroid with the lens. It contains

suspensory ligaments and ciliary muscles. Ligaments hold the lens in

position and ciliary muscles alter the shape of the lens.

Optic nerve- connects eye with brain. The region where the optic

nerve leaves the eye is known as the blind spot because it has no

photoreceptors so it can't produce an image. Carries nervous signals from

retina to visual cortex of the brain, which interprets them as, images.

2. a) Explain the term 'refraction' in...