Eyes

• Location of rod and cone cells in retina


  • Rod: evenly distributed around periphery but NOT in central fovea
  • Cone: mainly central fovea no photoreceptors at blind spot
• Types of photoreceptor cells in the retina


  • Cone cells
  • Rod cells
• Rod cells


  Evenly distributed around periphery but NOT in central fovea
• Cone cells


  Mainly central fovea, no photoreceptors at blind spot
• Pigment


  • Rod: rhodopsin
  • Cone: 3 types of iodopsin
• Visual Acuity


  • Rod: Low res, many rod cells synapse with 1 bipolar neuron
  • Cone: High res, 1 cone cell synapses with 1 bipolar neuron= no retinal convergence
• Colour sensitivity


  • Rod: Monochromatic, all wavelengths of light detected
  • Cone: Tricolour, red, blue, green wavelengths absorbed by different types of iodopsin
• Light sensitivity


  • Rod: V.sensitive, spatial summation of subthreshold impulses
  • Cone: Less sensitive, not involved in night vision
• Pathway of light from photoreceptor to brain

  Photoreceptor → Bipolar neuron → Ganglion cell of optic nerve → Brain
• Photoreceptor cells in retina


  • Cone cells
  • Rod cells
• Location of rod and cone cells in retina

  • Rod: evenly distributed around periphery but NOT in central fovea
  • Cone: mainly central fovea no photoreceptors at blind spot
• Types of photoreceptor cells in the retina

  • Cone cells
  • Rod cells
• Rod cells


  Evenly distributed around periphery but NOT in central fovea
• Cone cells


  Mainly central fovea, no photoreceptors at blind spot
• Pigment


  • Rod: rhodopsin
  • Cone: 3 types of iodopsin
• Visual Acuity


  • Rod: Low res, many rod cells synapse with 1 bipolar neuron
  • Cone: High res, 1 cone cell synapses with 1 bipolar neuron= no retinal convergence
• Colour sensitivity


  • Rod: Monochromatic, all wavelengths of light detected
  • Cone: Tricolour, red, blue, green wavelengths absorbed by different types of iodopsin
• Light sensitivity


  • Rod: V.sensitive, spatial summation of subthreshold impulses
  • Cone: Less sensitive, not involved in night vision
• Pathway of light from photoreceptor to brain

  Photoreceptor → Bipolar neuron → Ganglion cell of optic nerve → Brain