Sheep Eye Dissection Analysis

We dissected a sheep's eye in class, here's some labeled photos that were taken during the dissection as we went step by step through the whole thing. On the topic of dissecting a sheep's eye, we were able to see and learn about the anatomy of our own eye essentially, since a sheep's eye is very similar to that of a human. The parts of the eye that we identified are the lens, the suspensory ligament, extrinsic muscle, retina, tapetum lucidum, sclera, vitreous humor, eyelid, optic nerve, fatty tissue, cornea, extrinsic muscle, pupil, iris, and ciliary body. The pupil is the hole in the eye where light can enter, the size of the pupil is regulated by the iris, which either expands or contracts the pupil depending on the amount of light. The lens of the eye is suspended a bit behind the pupil by the suspensory ligament, which is connected to the ciliary body. The ciliary body is able to change the shape of the lens very slightly to adjust the light so that it hits the retina. The retina is what detects the light and produces colors, using rods and cones. In the eye of a nocturnal animal, behind the retina is the tapetum lucidum which allows animals to see better in the dark and is also the reason why when you take a picture of some animals, their eyes will seem to be glowing. In the middle of the eye is the vitreous humor, which is a clear jello-like substance that helps the eye maintain it's shape. Around the inside of the posterior part of the eye is the choroid, which is dark and thin, it brings nourishment through the posterior end of the eye. The cornea is the thin layer that is at the anterior end of the eye and goes over the pupil and iris, with some aqueous humor (liquid), found behind it. Two things that effect the eye are cataract and glaucoma. Cataract is when because of aging, the lens turns cloudy and it reduces the amount of light that is able to reach the retina. Glaucoma is when the fluid pressure of the aqueous humor and vitreous humor becomes too high, which causes eye damage.