Exercise 2

Exercise Two

Group Members: Justine Galea, Katie Goulet and Nicole Hieter

In the first class our group was given the task of drawing a system model of the sense sight.  Using our knowledge from the science classes of our  youth, we put together a diagram that gave a general idea on how the human eye worked.

Now, for exercise two we've been asked to to elaborate on our original idea and correct the mistakes we had made.  The main issue with our diagram was that we were missing quite a few components of the eye; such as the the Optic Disk located in the back of the eye, the Choroids which supply the eyes with blood and the Sclera which is the fibrous tissue that holds the eyes together.  Also within the eye, there is the Vitreous Fluid, a gel like substance that gives the eyes shape.  One large mistake we had made on our diagram was how we put the Cornea in the back of the eye thinking it was the "screen" that our vision gets caught on and flipped upside down to be fed to our brain.  However, the Cornea actually surrounds the eye and protects the Lens and Iris.

Finally, there was the question of "What exactly are rods and cones"?  At last, we have an answer.   They are Photoreceptor Cells that make up the Retina.  Rods deal with light sensitivity; they are what blind you in the sun light and allow us to see in the dark.  Cones on the other hand separate light and tell our brains what colours we are seeing.  For cones to work, they need a greater amount of light than the rods require.

Hartzog, Kevin. Vision. 2002. January 9.

http://www.startsandseas.com/SAS%20Physilogy/Neuroloy/Sight.htm