the nervous system and the eye

• Brain

  Controls complex behavior
• Brain

  • Made of billions of interconnected neurones
  • Has different functions
• Main regions of the brain

  • Cerebral cortex
  • Cerebellum
  • Medulla
• Nervous system

  Enables humans to react to their surroundings and coordinate their behavior
• The complexity and delicacy of the brain makes investigating / treating disorders very difficult
• Retina


  • Contains receptor cells that are sensitive to light
• Visual information processing

  1. Impulses from the receptor pass along a sensory neurone to the CNS

  2. An impulse then passes through a relay neurone

  3. The motor neurone carries an impulse to the effector
• Neurones are not directly connected to each other, they communicate with each other via synapses (gaps between neurones)
• Sclera


  • Forms a tough outer layer, with a transparent region at the front called the cornea
• Iris


  • Controls the size of the pupil and the amount of light reaching the retina
• Ciliary muscles and suspensory ligaments

  • Can change the shape of the lens to focus light onto the retina