01:830:331 Lecture 25: lecture 25
24 Jul 2016
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Document Summary
~photoreceptors are rods and cones, are in the retina. ~each retina has like 120 million rods and 6 million cones. ~cones provide visualization of fine detail, provide acuity (sharpness) ~fovea is a small pit in the geometric middle of the retina, has exclusively cones, packed together. ~in dim lighting, we are color-blind, use rod vision, don"t have foveal vision. ~optic disk (aka optic nerve head) is the point of entry for the axons of neurons in the eye gather and leave through the optic nerve to send info to rest of brain. No rods and cones in this area, so it"s a blind spot. ~the retina has many layers of neuron cell bodies. Outermost is ganglion cell layer (light goes through here first) ~light needs to pass through ganglion and bipolar cell layers to get to photoreceptor. ~bipolar cells have one inner pole synapsing with photoreceptors/horizontal cells and the other outer pole synapsing with ganglion cells/amacrine cells.
