Eye

• Diagram of eye

  • Sclera = tough outer layer
  • Muscles in iris = control size of pupil
  • Fovea = in retina, has high conc of rod & cone cells
  • Optic nerve = electrical impulses travel along this to brain (lacks rod & cone cells - blind spot

  
• radial + circular muscles - antagonistic - control amount of light entering the eye
• pupil dilation

  • radial muscles contract
  • circular muscles relax
  • sympathetic response (pupil constriction is parasympathetic response)
  • to let light in, in dark conditions