February 6, 2012

2.86 The Eye

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

The eye is a photoreceptor that detects changes in visible light. When light stimulates the rods in the back of your eye a nerve impulse is sent to the brain along the optic nerve, your brain then interprets these impulses to make a picture.

  • Ciliary muscles – Contract or relax to alter the shape of the lens (to focus)
  • Cornea – Transparent cover allows light in and does most of the bending of light.
  • Iris – Alters pupil size (to vary light intake)
  • Vitreous Humour – Clear jelly that gives the eye ball shape
  • Lens – changes shape to focus light on the retina
  • Retina – Contains the light-sensitive receptor cells which change light into electrical impulses
    • Rods – sensitive in dim light but only sense black and white
    • Cones – sensitive in bright light and can detect colours
  • Sclera – Protective tough outer layer of the eye
  • Suspensory ligaments – Hold the lens in place
  • Optic nerve – Carries the electrical impulses to the brain
The Gif below shows the human eye dilating due to a change in light intake this is controlled by the Iris

No comments:

Post a Comment