ABSTRACT

Sensory receptors generate a receptor potential, a change in their membrane potential, in response to appropriate stimulation. This process is called transduction and is different in different receptors. For somatosensory systems the sensory receptor is the modified ending of the primary afferent neuron, and is depolarized directly by the stimulus. In other sensory systems the sensory receptor is a specialized cell type which forms synaptic connections with the first afferent neuron. Here, alterations in membrane potential alters sensory cell neurotransmitter release, with effects on the primary afferent. In vertebrates, all sensory receptors, except photoreceptors, depolarize when stimulated. Photoreceptors are hyperpolarized by light.