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The Sensory
System
Sensory receptors are specially modified nerve
endings that convert stimuli from the environment into nerve impulses
that are transmitted to the central nervous system.
There are 4 general types of stimuli to which the
sensory receptors of common animals are sensitive:
 | mechanical |
| thermal |
| electromagnetic |
| chemical |
General terminology
| esthesia = ability to receive sensory
information |
| gustatory = taste |
| ocular, ophthal- = eye |
| olfactory = smell |
| tactile = touch |
| noci = pain |
The General Senses are widely distributed
around the body. Their sensory receptors are not highly
specialized.
| visceral sensations = "interior" sensations
such as hunger & thirst |
| touch (and pressure) |
| temperature |
| proprioception = body position
& movement |
| pain |
The Special Senses are all concentrated in
the head. Their sensory receptors are more highly specialized than
those of the general senses.
| taste
- sensory receptors are located in "taste buds" |
| smell - the olfactory epithelium is located
high in the nasal passages. The olfactory cells detect chemical
substances that dissolve in the mucus overlying the sensory
cells. |
| hearing |
| equilibrium |
| vision |
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