Our senses allow us to communicate with the outside world. What we smell, hear, taste, touch and see direct our actions. But it is vision that dominates our impressions of the outside world. We use this sense every moment when we are awake and we even dream in visual images while we sleep. We blink. We stare. We cry. Our eyes not only interpret what we see, but they allow us to communicate our feelings and emotions. Each of us sees the world differently. Through the miracle of the eye, we take in the world around us and make it our own.
Your eye has the amazing ability to convert light into a stream of nervous impulses. Light is directed through the eye and an image of what we see is projected on the retina, at the back of the eye. Neurons then take information about this image to the brain for processing and interpretation. Each structure in the eye plays a unique role in assuring that the image you see is the image before you.
One way to figure out how something works is to look inside it. In this activity, you will use your power of sight to learn about the power of sight. To investigate how the eye works, you will dissect a cow’s eye and observe its unique structure. As you complete the dissection, see if you can figure out the specific function of each part of your eye. Observe how all the parts of an eye work together to allow you to take in a brilliant sunset, an exciting sporting event, or a scary movie.
Procedure View the drawing of the eye found at the Exploratorium site http://www.exploratorium.edu/learning_studio/cow_eye/eye_diagram.html and copy this labeled drawing into the space below, using color and labeling all parts or making a key.
Fill in the table below to describe the function of each eye part. Put the cursor over the labeled eye part of the pervious website to get the description. You may have to do some additional research for the functions. Some website that may help are:
Exploratorium: The Eye http://www.exploratorium.edu/learning_studio/cow_eye/eye_diagram.html
Neuroscience for Kids: The Eye http://faculty.washington.edu/chudler/bigeye.html
The layer of light sensitive cells at the back of the eye. The retina detects images focused by the cornea and the lens. The retina is connected to the brain by the optic nerve.
A tough, clear covering over the iris and the pupil that helps protect the eye. Light bends as it passes through the cornea. This is the first step in making an image on the retina. The cornea begins bending light to make and image; the lens finishes the job.
The pupil is the dark circle in the center of your iris. It’s a hole that lets light into the inner eye. Your pupil is round. A cow’s pupil is oval.
A clear fluid that helps the cornea keep its rounded shape.
A muscle that controls how much light enters the eye. It is suspended between the cornea and the lens. A cow’s iris is brown. Human irises come in many color, including brown, blue, green and gray. It gives you your eye color!
A clear, flexible structure that makes an image on the eye’s retina. The lens is flexible so that it can change shape, focusing on objects that are close up and objects that are far away.
The thick, clear jelly that helps give the eyeball its shape.
The thick, tough, white outer covering of the eyeball.