NESC 2570 Lecture Notes - Ion, Photoisomerization, Cyclic Nucleotide
26 Nov 2012
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Document Summary
Light enters the eye, and travels to the back of the eye where the rods and cones are located. Rods and cones transduce using the same transduction scheme: but they are both sensitive to different wavelengths. Most eye diseases result from problems in the photoreceptors: since they are very metabolically active cells. The other classes of eye diseases result from damaged ganglion cells: usually just from natural cell death. In dark: have light sensitive molecule rhodopsin. Signal to cyclic nucleotide gated channels (cng channels) Since the channels are non-selective, tend to depolarize the membrane toward 0mv. There are also voltage gated potassium channels. Bring the rods back to resting potential: resting potential is -40mv. In light, membrane potential goes to -50 to -60mv. It plays a role in adaption: voltage gated channels present in the feet of the receptor for synapses like normal neurons. Enzyme that finds gtp, and turns it into cgmp.
