Download Cow Eye Dissection

Cow Eye Dissection
Purpose: To examine the parts of a cow eye that are important in vision
Materials:
preserved cow eye
Dissecting tray
Tweezers
scissors
razor blade or scalpel
Procedure & Write-up
Part 1 – The External Eye
1. Examine the outside of a preserved cow eye. Locate the parts listed in table 1.
Eye muscles
Fat
Optic nerve
Sclera
Cornea
EXTERIOR EYE
Along the top, bottom, and sides of the eye; thick tough bands of
pink tissue.
Yellow; surrounds back of eye; may cover some muscles
At very back of eye; pink and as thick as a pencil; may be
surrounded by fat and muscle.
Tough, whiter outer covering of eye; easily seen at the front of eye
Clear covering at front of eye
2. Label the following diagram using the part from table 1. Draw in the places where
you found fat. (6 pts)
Diagram 1
Part 2 – The Internal Eye
**Make an incision through the cornea releasing the aqueous humor.
1. Using scissors and tweezers, remove as much fat and muscle from the eye as possible.
2. Leave the optic nerve.
3. Try to pull some of the eye muscle away from the sclera.
Q1. Is it easy to remove the muscle?
Q2. Why might there be so much fat around the eye?
4. Once the fat and muscle are cleaned off cut through the eye as in diagram 2.
Q3. Is the sclera thick or thin?
Q4. Is the sclera tough or was it easy to cut.
5. Once the eye is cut in half, locate the lens, retina, pupil, and vitreous humour.
6. If the lens has not fallen out, remove it carefully with the tweezers.
7. Hold the lens over some printing on a page.
Q5. Can you see the printing through the lens?
Q6. Move the lens back and forth. What happens to the size of the printing?
Q7. Whay type of lens is this? How do you know?
Conclusion: Write a paragraph conclusion describing your dissection of the eye. You
might also want to include what you learned concerning how the eye works. (7 pts)