The Nervous System, Sensory Receptors; Neuronal Circuits for Processing Information
SENSORY RECEPTORS Five basic types of Sensory Receptors Mechanoreceptors Thermoreceptors Nocioreceptors Photoreceptors Chemoreceptors Sensory Receptors are highly sensitive to one particular type of stimulus - "the labeled line" priciple. sensory modality anteriolateral system (spinothalamic tract) - pain Receptors transduce a physico-chemical stimulus into a Nerve Impulse The Sensory fiber linked to each receptor exhibits "threshold phenomena" The receptor potential is proportional to stimulus intensity frequency Sensory receptors adapt their stimuli either partially or completely over time accomodation Receptors are classified as slowly adapting or rapidly adapting Slowly adapting receptors Tonic receptors Rapidly adapting receptors rate receptors or movement receptors Physiological Classification of receptors Two different schemes have been devised to classify the entire range of peripheral nerve fibers Types A and C Fiber diameter and c