Sensory Transduction 10/19/2015 Sensory Receptor cell: when sensation impinges upon your body cells become more positive Vision The qualities of light The lens that had been flat becomes rounder and brings light into better focus in the back of retina. Light comes in and focuses on the retina. They hit the photoreceptors (rods and cones). The cells do photo transduction. The light has to change cells electrically Photoreceptors have particular molecules that respond to light. The molecules are called rhodopsin. When light shines on them, the rhodopsin changes shape. They go from curvy` to straight. Activates chemical How does light cause electrical changes in a cell? o In the dark, ion channels are open. Sodium can move in through there. It releases an inhibitory neurotransmitter called glutamate. Once light is shined on it, it becomes more negative (hyperpolarized). Light actually causes ion channels to close. Sodium can’t leak into the cell so cells become more negative. Light is going to make cells become negative. (when
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- Fall '08
- binding sites, action potential frequency