1. THE EYES AND VISION

4. The fovea centralis
The fovea is literally a “pit” formed by parting of the neural layers. In this region, light falls directly on the photoreceptors (cones).

7. The Retina

9. THE BLEACHING REACTION
In the presence of light
If you look at the color for too long, you will not see the color briefly.

10. DARK:
Cell is depolarized
Sends an inhibitory neurotransmitter to bipolar cells
LIGHT:
Cell is Hyperpolarized
Does not send an inhibitory neurotransmitter to bipolar cells
Bipolar cells send excitatory neurotransmitter to ganglion cells,
which activate the optic nerve.

11. Summary slide

12. The Cones
do not have rhodopsin
do have retinal and undergo bleaching
have 3 photopsins that allow us to see 3 different wavelengths of light
Dichromatic vision is in most animals
Trichromatic vision
is in humans and old world primates like chimps and gorillas
most likely evolved from a duplication of the gene for green located on the X chromosome, which may have led to a gene for red color vision on the X chromosome
Males are most likely to be red or green color blind