PSYCH 2E03 Lecture Notes - Cyclic Guanosine Monophosphate, Photopic Vision, Scotopic Vision
13 Jun 2013
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Document Summary
Accumulation of retinal is harmful to the retina. *know steps of rhodopsin breakdown retinol being stored and converted to retinal continuously. Importance of retinal-retinol cycle retinal (an aldehyde) toxic in large amounts retinol (an alcohol) stored in pigment layer. Dark: inner segment of rods and cones, sodium and calcium continuously leak into receptor, more glutamate light: sodium calcium is no longer permitted to enter, less glutamate. Phototransduction: amplification/cascade small change in the pigment leads hundreds of enzymes cascade. The phototransduction cascade trans-retinal (and formation of metarhodopsin ii) transduction (g-protein_ No cyclic gmp stop ca2+ and na+ entry. Higher convergence in the rod-system makes them more sensitive to light than the cones sensitive to low light intensity less-convergent cones are better at sharpness/discreetness (acuity) of vision than the rods. As we come towards the fovea, light reaches the cones uninterrupted because of the way the receptors and the bipolar/ganglion cells are placed.
