Sheep Eye Dissection Analysis

 In this lab, we used sheep eyes to develop a deeper understanding of the structure of an eye. We examined the eye from an external view as well as internally once dissected.

Sclera, white tissue

We know that the sclera, or the whites of the eye is tough and fibrous to protect the cornea and internal eye, and so in order to view the internal anatomy we must cut through it.

Optic nerve  

Similar to the sclera, the cornea also serves as protection, controls the entry of light and is the outermost lens of the eye
We noticed the optic nerve that projects from the back of the eye; it transmits signals to the brain through ganglionic (nerve) cells

Once making a frontal cut into the eye, we are able to see the two hemispheres revealing the retina, vitreous humor and choroid.


To the left we can see the retina peeling away from the choroid to reveal the tapetum lucidum, which reflects light onto the retina so that animals can see better in low lights. Humans do not have this, which explains why animals have better night vision.

The vitreous humor maintains the shape of the eye and once scraping it away the lens was revealed. The pupil lies inside the iris and is a small opening that regulates the amount of light that enters the eye.

Eyes contain sensory cells called rods and cones. These help to see shades of grey and different colors.
When light enters the eye it follows a pathway that leads it to the optic nerve. It enters the cornea, which focuses our vision. It goes through the gelatinous aqueous humor which gives the eye structure. Entering the iris, the pupil controls how much light goes through depending on the surroundings, (kind of like aperture on a camera). It travels through the vitreous humor which separates the retina from the pupil which contains the rods and cones. Finally, the optic nerve sends this information to the brain for processing.