1. 26 / Tuesday
Kuapapa:
Dissect a cow’s eye to observe and describe the structure of eye

2. cornea
iris
sclera (white coat)
lens
retina
pupil
optic nerve

3. Eye Dissection

6. Sclera: the white, tough, outer covering
Examine the outside of the eye. How many parts of the eye can you identify?
Sclera: the white, tough, outer covering
Cornea: the clear covering over the front of the eye
Iris: the coloured part of the eye
Pupil: the dark oval in the middle of the iris
Source: adapted from www.

7. Cut away the fat and muscle
Make an incision in the cornea
Release all the clear liquid
This liquid is the aqueous humor which is mostly made of water and helps keep the shape of the cornea

8. Make an incision in the sclera in the middle of the eye
Cut around the middle of the eye
You’ll end up with two halves
Remove the cornea from the front half and place it on the cutting board
Try cutting through the cornea
– why is it so strong?

9. Pull out the iris – it should be between the cornea and the lens, but may have stayed with the back of the eye
The hole in the centre of the iris is the pupil, which lets light into the eye
Remove the lens
It is a clear lump about the size and shape of a squashed marble

10. The lens feels soft on the outside and hard in the middle
Hold the lens up and look through it – what do you see?
Put the lens down on a newspaper and look through it at the words – what do you see?

11. The back of the eye is filled with a clear jelly, called vitreous humour, which helps the eyeball keep its shape – why is it clear?
On the inside back of the eye, you can see some thin film with blood vessels – this is the retina
Push the retina around and find where it is attached to the back of the eye
This is the blind spot, which is the start of the optic nerve, which carries the electrical signals detected by the retina to the brain

12. Under the retina, the back of the eye is covered with shiny, blue- green tapentum
It reflects light from the back of the eye
Look at the other side of the back of the eye
Squeeze the optic nerve to see the separate fibres
Some white goo may ooze out – this is myelin which is a fatty layer that protects each fibre