Sheep Eye Dissection Analysis

In this lab, my partner and I dissected a sheep eye and were able to identify all internal and external structures of the eye. On the outside, we were able to identify the cornea, which appeared cloudy and is the first structure that light passes through. It is also the protective layer of the eye. We also identified the sclera, the very hard exterior of the eye, this is also the white of the eye. Next, we located the optic nerve, which is the second to last step in the path of light as it sends the information to the brain and the brain is able to process it into vision. Then we found the external eye muscle that allows our eye to move up, down, left, and right. Finally, we identified the fatty tissue. This was white and yellow in color and gives the eye cushioning.

For the second part of the lab, we cut into the eye to identify the interior anatomy of the eye. Cutting through the sclera was difficult, as it was quite tough. When we finally cut all around the eye, we identified the vitreous humor that resembled a jelly like substance. There is also the aqueous humor, which is located behind the cornea. Both the vitreous humor and aqueous humor help to maintain the shape of the eye. When we removed the retina, it revealed the choroid layer which was a thin black layer found in-between the sclera and the retina. In one place, the retina is firmly attached to the choroid. This part is known as the blind spot. Next, we removed the choroid which revealed the tapetum lucidum, that helps animals with their night vision as it functions to reflect light onto the retina.

Finally, we removed the vitreous humor and the lens to reveal the ciliary body. The ciliary body appears ridged. We then identified the lens. When the lens appears cloudy, that means it has a condition called a cataract. A cataract prevents or reduces the amount of light that reaches the retina. Then, we identified the pupil which is the opening in the center of the iris. Pupil size increases with decreased light intensity and decreases with increased light intensity. Lastly, we removed the cornea from the front of the eye and made small cuts in it. We noted that it was very thick, mostly likely to act as protection for the eye.