Friday, February 11, 2011

Cow Eye Dissection

The aim of this experiment is to examine the interior of the eyes to better understand how the eye functions and to explore the different parts of the eye. The experiment will require a cow eye, some goggles and a dissection kit.

Record your observations as you cut the eye.
  1. Cut away the fat and muscle on the outside of the eye. It should expose the optic nerve.
  2. Use the scalpel to make an incision through the sclera in the middle of the eye, and then use a pair of scissors to cut the eye in half.
  3. Remove the vitreous humor to reveal the lens.
  4. Remove the lens to see the iris and pupil.
  5. Investigate the lens by cutting it in half.
When we receive the eye, the first thing we noticed was the smell. Since the eye was not fresh, it was a very strong smell to it that I did not like too much. It made me want to vomit. Although you nose becomes acclimated to the smell after a couple of minutes, it is initially quite unbearable. After removing the fat and muscle from the outside of the eye, we can see the optic nerve, which has a radius of roughly 0.25 cm. The entire eye has a radius of roughly 2 cm.

As you cut open the sclera, we noticed that the sclera has a strong structure that helps the eye keep its shape. Cutting the sclera felt like cutting up leather. The vitreous humor is revealed after the eye is cut in half. It is clear gelatinous substance that is almost like water, but is still able to keep some of its shape after being removed from the eye. We estimate that its volume is around 8.4 cm3.

The lens has a radius of between 0.5 and 0.75 cm. As the eye was not fresh, the lens has become opaque and therefore we could not see through it. It has also hardened. Cutting the lens in half revealed that the eye has onion-like layers.

After we remove the lens, we can see the iris and the pupil. The iris is very dark and has a radius of around 1.5 cm. The pupil has a radius of 0.5 cm and is next to the aqueous humor. While investigating the other side of the eye, we see that all the optical nerves mesh together to form a film-like layer. It is black so that it can absorb like from a wide spectrum.

We used a cow eye because the eye was very similar to a human eye, and dissecting the eye helped us gain a better understanding of how the eye functions.

1 comment: