the brain and eye

• what does the cerebral cortex do?

  responsible for things like intelligence and memory
• what does the cerebellum do?

  responsible for muscle coordination
• what does the medulla do?

  controls unconscious activities like breathing and heart rate
• what does the cornea do?

  refracts light into the eye
• what does the iris do?

  contains muscles that allow it to control how much light enters the eye
• what does the lens do?

  focuses the light onto the retina
• what do the cilary muscles and suspensory ligaments do?

  control the shape of the lens
• what does the optic nerve do?

  carry impulses from the receptors on the retina to the brain
• the brain is made up of millions of interconnected neurones
• what are the methods to study the brain?

  • electrically stimulating the brain
  • MRI scans
  • studying people with brain damage
• what does the sclera do?

  supports the wall of the eye
• when there is a bright light the light receptors detect it and a reflex is triggered to make the pupil smaller. the circular muscles in the iris contract and radial muscles relax - reducing the muscles in the eye
• when the light is dim the ciliary muscles relax and the radial muscles contract - increases the light that enters
• to look at near objects the ciliary muscles contract and the suspensory ligaments relax
• to look at distant objects the ciliary muscles relax and the suspensory ligaments tighten
• what happens if someone is long sighted?

  the lens is the wrong shape and doesn't refract light enough or the eyeball is too short

  the images are brought into focus behind the retina

  this is corrected by convex lenses

  the medical term is hyperopia
• what happens if someone is short sighted?

  when the lens is the wrong shape and refracts light too much or the eyeball is too long

  the images of the distant object are brought to focus in front of the retina

  it is corrected by a concave lens

  the medical term is myopia
• what are the 3 treatments for vision defects?

  contact lenses

  laser eye treatment

  replacement lens surgery