INTRODUCTION TO SENSORY TRANSDUCTION
Sensory transduction, the ability to detect and translate a stimulus, is an indispensable part of our lives. It underlies nearly every facet of life as we know it. As humans we believe in, or better we rely on, the five basic senses of sight, hearing, touch, taste, and smell. Indeed our whole perception of the world is based solely on our interpretations of these 5 senses (in the forms of their basic properties, light, sound, pressure, chemical, and others generally lumped into the "touch" category). However many living organisms rely on alternate or additional senses in order to percieve their environment. These include heat, gravity, acceleration, electrical and magnetic fields, the passage of time, and probably some that we haven't detected yet. Regardless of what is detected sensory systems follow the same sensory transduction pathway: Detect--->Amplify--->Signal. The last two are generally similar in different modalities, modes of detection, i.e. light, sound, etc., however the methods of detection obviously vary
depending on the stimulus to be detected.
There are may classification systems for sensory receptors, one is particularly useful. Developed by Charles Sherington, the system classifies the receptors based on the source of the stimulus. Interoreceptors transduce information from within the organism. Proprioreceptors transduce information regarding the body parts in relation to one another. Exteroreceptors transduce information from outside the body and can be further subdivided into two additional categories teloreceptors and somatoreceptors. Teloreceptors deal with stimuli which are away from, as in not touching, the body. Somatoreceptors transduce stimuli and events that occur on the body's surface. As stated earlier the type of stimulus that a receptor detectects is kown as it's modality. Within the above classificatio scheme there are obviously many different modalities appropriate to each category, and most modalities may be detected at various locations and distances.
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