the eye (triple)

• Eye


  A sense organ that contains receptors sensitive to both light intensity and color of light
• How light passes through the eye

  1. Light passes through the transparent cornea

  2. Light passes through the pupil in the center of the iris

  3. Light passes through the lens

  4. Light is focused onto the retina at the back of the eye
• Cornea


  • Starts the focusing of light rays
• Lens


  • Can change shape to focus light from distant or near objects (accommodation)
• Retina


  • Contains receptor cells that detect light intensity and color
  • Sends electrical impulses down the optic nerve to the brain
• Sclera


  • Tough outer structure that protects the eye
• Ciliary muscles and suspensory ligaments

  • Work with the lens to allow focusing on distant or near objects
• Iris


  • Colored part of the eye
  • Controls the size of the pupil to regulate the amount of light entering the eye
• Pupil size adjustment in response to light

  1. Dim light: Pupil dilates to allow more light to enter

  2. Bright light: Pupil constricts to reduce light entering
• Pupil size adjustment is a reflex action, not controlled by the conscious part of the brain