Procedure for your cow’s eye dissection

Name:________________________ Date:__________________

Check off steps as you complete them. Make notes if you have any trouble.

1. Examine the outside of the eye. See how many parts of the eye you can identify. Find the whites (or sclera) and the clear covering over the front of the eye (the cornea). You should also be able to identify the fat and muscle surrounding the eye.

a. _______ I found the sclera
b. _______ I found the cornea
c. _______ I found the muscles
d. _______ I found the fat

2. Make the first incision where the sclera meets the cornea. Cut until the aqueous humor is released.

a.________ Completed

3. Rotate the eye and cut around the cornea. Do not cut too deep or you may cut the lens. As the cornea starts to come free, hold the cornea in the center and make the last cuts around it.

a. ________ Completed

4. Once you have removed the cornea, place it on the cutting surface. Cut it with your scalpel or razor.

a. ________ Completed

5. With the cornea removed, pull out the iris. Place one finger in the center of the eye. Find the iris and pull it back. It should come out in one piece.

a. ________ Completed

6. Take your time as you remove the lens with the vitreous humor attached. Cut slits in the sclera first. Do not cut the lens.

a. ________ Completed

7. After enough incisions have been made in the sclera, you should be able to remove the lens. Sometimes the vitreous humor will be removed along with the lens.

a. ________ Completed

b. ________ The vitreous humor was removed

8. Hold up the lens and look through it. If the lens is too slippery, pat it dry and try again.

a. ________ Completed

b. ________ What did you notice about the lens?

9. Remove the vitreous humor if you didn’t in step 8 Turn the eye inside out.

a. ________ Completed

10. The thin tissue on the back of the eye is the retina. Find the spot where the retina is attached. The shiny blue-green material is the tapetum.

a. ________ Found the tapetum

11. Find the spot where all the retina's nerves collect. This is the blind spot. This is where all the nerves go out the back of the eye, forming the optic nerve.

a. ________ Found the blind spot

12. Locate the optic nerve on the outside of the eye. To see the separate fibers that make up the optic nerve, pinch the nerve with a pair of scissors or with your fingers.

a. ________ Found the optic nerve

b. ________ Separated the fibers

13. Once the dissection is complete, clean up. Properly dispose of the remains by wrapping them in plastic and disposing immediately. Also, if you used razor blades, wrap in a paper towel and dispose. Clean up your area.

a. ________ Completed

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