Sheep Eye Dissection

The eyeball

Cornea and sclera visible 

Retina (peeling off), choroid, and tapetum lucidum (top)

Lens and vitreous humor (bottom)

The lens

First, we looked at the outside of the eye, where we saw the sclera (the white of the eye), the cornea (which is where the light goes through), and lots of fatty tissue on the back. We then cut off most of the fatty tissue in  order to see the optic nerve, which sends electrical impulses to the brain, which then interprets them, letting you see. We then cut the eye in half, so we could see the retina, which converts the light hitting it into electrical impulses using cells called rods and cones, on the back, and in the middle of it was the blind spot, which is where the retina meets the optic nerve. We then peeled back the retina so we could see tapetum lucidum, which helps to give the sheep better night vision, and the choroid, which functions as a supplier of blood for the eye. We then looked at the front half of the eye and saw and the lens, which bends the light coming in from the pupil, and the vitreous humor, a clear jelly-like mass that helps the eye retain its shape. We then took out the lens and vitreous humor so we could see the ciliary body, which is a muscle that controls the shape of the lens, the suspensory ligament, which connects the lens and ciliary body, and the pupil. 

By dissecting the sheep's eye, we were better able to understand the path of light through the eye. We saw the cornea, where light first passes through, and the pupil, which is the hole between the cornea and lens, as well as the iris, which controls the size of the pupil. We also saw the lens, which bends the light, and the vitreous humor, which light also passes through. The size of the lens surprised me; I thought it would be much thinner, and a little smaller. Finally, we saw the retina, which is where the light hits and is transferred into electrical impulses, and the optic nerve, which caries those impulses to the brain.

Parts of the eye