The Human EyeBy Emma Clarke

IntroductionSight is one of the most important senses. Eyes detect light and allow us to see. Although we can function without vision, we rely heavily on sight in our everyday lives. The eye is a fascinating organ that is made up of several parts working together to allow us to see. What do you think the most important sense is?

Parts of the human eyeCornea: the clear, dome-shaped tissue covering the front of the eyeIris: the coloured part of the eye, it controls the amount of light that enters the eye by changing the size of the pupilLens: a structure located just behind the iris – it focuses light onto the retinaOptic Nerve: the nerve that sends the message from the retina to the brain.Pupil: the opening in the centre of the iris – it changes size as the amount of light changes (the more light the smaller the circle.)Retina: a tissue that lines the back of the eye. It contains millions of photoreceptors (nerves that turn information into images.)

The eye and the brainThe eye and the brain work together as a team:The info our eyes receive is sent to our brain along the optic nerve. The brain processes this info and helps us to make the right decisions. Example: if there is an object coming your direction, you will move quickly out of the way!!!Sometimes there is not much info for the brain to work with, so it uses other info to understand what it is seeing. EXERCISE

Dilation and ContractionDilation and contraction happen when the size of the pupil changes according to the amount of light entering the eye.Dilation is when the pupil gets bigger in dim light and contraction is when the pupil gets smaller in bright light.REMEMBER: The more light, the smaller the pupil!

A child’s disease of the eyeConjunctivitis or pink eye:This is an inflammation or infection of the thin piece of tissue that covers the white of the eyes and of the inner eyelid.It is contagious and can last as long as three weeks!It looks like this:

Eye facts for youWhen your eyes are open light travels into

them from the world outside .This source of light could be the sun or even a light bulb.

The picture on the retina (a layer at the back of the eye, sensitive to light)is actually, believe it or not, upside-down, but your brain flips the image, allowing you to see the right way up.

Around 95% of animals have eyes. Some are very simple just picking up light and dark conditions.

Did you know?The most used muscle in your body is the muscle in your eye? Just think about how many times your eyes move when you look around. Now think about how many times you look around everyday. And every month. AND EVERY YEAR !!!!!!! That’s a lot of moving!!!

Hope you liked the project!!!! Keep on looking….