23. Photoreceptors Compare the sizes of the photoreceptors outer segments, which one is bigger? Three Main Parts: a. Outer Segments b. Cell body c. Synaptic terminal Outer segments
36. Types of Color Blindness Monochromacy Rod or Cone – very rare, All rods or all cones are missing Dichromacy – Two types of photoreceptors are present Protanopia – red cones are missing Deuteranopia – green cones are missing Tritanopia – blue cones are missing Anomalous Trichromacy - All three photoreceptors are present but there is a spectral shift Protanomaly- spectral sensitivity of red cones are shifted Deuteranomaly – spectral sensitivity of green cones are shifted Tritanomaly – spectral sensitivity of blue cones are shifted
37. NORMAL CONE SENSITIVITY CURVES (TRICHROMAT) B R G 437 nm 564 nm 533 nm NORMAL CONE SENSITIVITY CURVES (TRICHROMAT) Activity: Color blindness
38. B R 437 nm 564 nm Deuteranopia (no green cones; only red and blue) 1% of Males
39. B G 437 nm 533 nm Protanopia (no red cones; only green and blue) 1% of Males
40. R G 564 nm 533 nm Tritanopia (no blue cones; only green and red) Very rare
41. B R 437 nm 564 nm Most common Deuteranomaly (green shifted toward red) 5% of Males G
45. Gene Therapy for color blind monkeys All male squirrel monkeys are born only able to see mostly yellows and blues. It is difficult for them to distinguish reds from greens. Female squirrel monkeys can see the whole spectrum. What photoreceptor(s) do you think they lack? What advantage does color provide for these animals? Credit: Neitz Laboratory
56. Retinal Diseases Describe how the vision of an individual with Retinitis Pigmentosa is affected? Describe how the vision of an individual with Age-related Macular Degeneration is affected?