Sensory - Sensory 1)receptor responses to energy; limited...

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Sensory 1)receptor responses to energy; limited range but often very Sensitive • All receptor cells respond to some form of energy (light,heat, pressure, osmotic potential, chemical energy, etc.) • Receptors can detect only a very small part of the available stimuli in the environment. • They are often extremely sensitive to those stimuli they can detect. 2) events in stimulus detection; signal modifiction, sensory transduction. Sense organs detect and respond to stimuli in several stages: 1. Stimulus arriving at sense organ is often filtered or otherwise modified (usually, data of interest are amplified & extra data are ‘deleted’) by accessory structures:-- external ears, eyeball and lens, etc. 2. Modified stimulus is detected by a receptor cell, changing that cell’s electrical properties -- usually membranepermeability ( generator potential , etc.) sensory transduction 3. Change in receptor cell’s electrical properties causes a change in the frequency or number of action potentials on a sensory neuron Sensory systems and sense organs 3) logarithmic response to intensity; sensory accommodation Response is usually non-linear (logarithmic): lets a neuron code for large range of stimulus i ntensities with small range of APfrequencies. Receptors usually show sensory adaptation or accommodation: declining response over time to aconstant stimulus: * especially sensitive to changes in stimulus intensity! 4) mechanoreceptors: stretch, gravity, acceleration and movement
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This note was uploaded on 05/04/2010 for the course BIO 5B taught by Professor Chappell during the Spring '07 term at UC Riverside.

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Sensory - Sensory 1)receptor responses to energy; limited...

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