2.76 describe the structure and function of the eye as a receptor

2.76 •conjunctiva: •lubricates and protects the surface of the eye

       

         •cornea: •refracts light into the eye

                      •it’s transparent and has no blood vessels to supply it with oxygen so oxygen diffuses in

        

         •iris: •controls the diameter of the pupil and the light entering

         •lens: •focuses the light onto the retina (covered in light receptors - rods and cones)

                             •rods are more sensitive in dim light but can’t see colour

                             •cones are sensitive to colour but aren't so good in dim light 

                                        •cones are found especially in the fovea 

         •optic nerve: •carries impulses from the receptors to the brain