Friday, February 11, 2011

THE Cow Eye Dissection

Cow Eye Dissection

Intro- The motivation of this lab w

as to dissect and eye to learn more about the mechanics behind sight. We systematically took apart the eye and observed the interesting parts of the eye, determining their use.

Observations- Optical nerve is grayish, doesn’t seem like it can conduct electricity, almost seems like firm putty. Jelly like substance occupies the majority of the eye, curious because entering light will be bent as it enters this thicker medium, however the brain must take this into account. The substance must be for the eye to have some durability, so that it can be squeezed and not popped, and that if cut it wont deflate. A solid is not used so as to minimize the light bending effects. At the end of the eye there is a thin film of nerves where the sensory input happens. It is a thin film that is not attached to the skin of the eye, almost like a spider web on a piece of leather. The blind spot is clear; it is where the optic nerve leaves the eye. The nerves had a high density, and were slightly red tinted.

The back of the eye is flat, so as the image projected onto is isn’t bent further by a rounded eye. The lenses is interesting, it is very hard, feels like a piece of plastic, but not so hard as to make it brittle. The lens was definitely able to move when the cow was alive and it was kept moist, so as to be able to change where the focal point was. When the lens was cut open, it was like string cheese, breaking off into layers. This was no doubt to make it easy to bend, but the varying layers make for odd optical properties as if there was a variance in the density of the layers then light would be focused differently. The brain must be able to account for this, if this error occurs.

The lens is bowed out, so as the focus a large image into a smaller one that will be projected onto the back of the eye. Looking through the lens offered nothing, as it was too cloudy to see through. The slit in which light enters the eye is oddly rectangular, not circular. The cornea is around it and can change sizes to let in varying amounts of light, it acts like the foil at the end of the jet engine, it creates ridges and folds as it contracts the folds flatten out when it grows.

Conclusion- the eye is a wonderful thing. To see how something so magical and important to our existence can be broken down into beautiful natural biological phenomenon is powerful. The whole process of seeing is incredible, as it is incredibly effective and adaptable to changing scenarios and problems. It is a camera that has yet to be matched by modern technology, engineers could learn something about its incredible effect and efficient nature.

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