1. COW EYE DISSECTION
Use this presentation as your “virtual” cow eye dissection, or
use it as a guide for your actual classroom dissection
(recommended).
If you are following along at school, please be careful.
Scalpels and razors can cut you as easily as they cut cow eyes.
You can order cow's eyes at a butcher shop or purchase them
directly from a slaughterhouse. Try to get eyes with the
muscles and fat still attached. If possible pick up the cow's
eyes the day of the dissection, eyes are easier to cut when
they are fresh.

2. MATERIALS NEEDED:
-One cow's eye for every two participants. -One single-edged razor blade or scalpel -Scissors (optional) -Wax Paper and Paper Towels -Plastic garbage bag

3. STEP 1: EXAMINE EYE
Examine the outside of the eye. See how many parts of the eye
you can identify. You should be able to 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
surronding the eye.

5. STEP 2: FIRST INCISION Make the first incision where the sclera meets
the cornea. Cut
until the
aqueous humor
is released.

6. STEP 3: CORNEA Rotate the eye and cut around the cornea. Be
careful not to
cut too deep or
you may cut the
lens. As the
cornea starts to
cut free, hold
the cornea in
the center and
make the last
cuts around it.

7. STEP 4: CORNEA Once you have removed the cornea, place it on
the board (or
cutting surface)
and cut it with
your scalpel or
razor.

8. STEP 5: IRIS With the cornea removed, the next step is to 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.

9. STEP 6: SCLERA It can be a bit tricky to remove the lens with the
vitreous humor
attached. It works
best if you cut slits
in the sclera. Be
careful not to cut
the lens.

10. STEP 7: LENS 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.

11. STEP 8: EXAMINE LENS Hold up the lens and look through
it. If the lens is
too slippery, pat
it dry and try
again.

12. STEP 9: INSIDE OUT With the vitreous humor now removed, you
should be able to
turn the eye
inside out.

13. STEP 10: RETINA 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.

14. STEP 11: OPTIC NERVE Find the spot where all the retina's nerves
collect. It is called
the blind spot.
This is where all
the nerves go out
the back of the
eye, forming the
optic nerve.

15. STEP 12: OPTIC NERVE Return your attention to the outside of the eye.
Locate the optic
nerve. To see the
separate fibers
that make up the
optic nerve, pinch
the nerve with a
pair of scissors or
with your fingers.

16. STEP 13: CLEAN-UP
Once the dissection is complete, properly dispose of the
remains. They should be wrapped up in plastic and disposed
of the same day. Also, if you used razor blades, they should
be disposed of properly. (A blade is good for only one or two
dissections.)