| BBC - GCSE Bitesize - Biology | Humans | The eye: function |
| Our eyes are sense organs which respond to changes in light. The eye's receptors are specialised light-sensitive cells called photoreceptors, which line the inside of the eye and form a lig... |
| http://www.bbc.co.uk/schools/gcsebitesize/biology/humansasorganisms/4nervoussyst... (Ask.com) |
