Sensory neuron

Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded receptor potentials. This process is called sensory transduction. The cell bodies of the sensory neurons are located in the dorsal ganglia of the spinal cord. The sensory information travels on the afferent nerve fibers in a sensory nerve, to the brain via the spinal cord. The stimulus can come from exteroreceptors outside the body, for example those that detect light and sound, or from interoreceptors inside the body, for example those that are responsive to blood pressure or the sense of body position. == Types and function == Different types of sensory neurons have different sensory receptors that respond to different kinds of stimuli. There are at least six external and two internal sensory receptors: Information coming from the sensory neurons in the head enters the central nervous system (CNS) through cranial nerves. Information from the sensory neurons below the head enters the spinal cord and passes towards the brain through the 31 spinal nerves. The sensory information traveling through the spinal cord follows well-defined pathways. The nervous system codes the differences among the sensations in terms of which cells are active. A sensory receptor's adequate stimulus is the stimulus modality for which it possesses the adequate sensory transduction apparatus. Adequate stimulus can be used to classify sensory receptors: Baroreceptors respond to pressure in blood vessels Chemoreceptors respond to chemical stimuli Electromagnetic radiation receptors respond to electromagnetic radiation Infrared receptors respond to infrared radiation Photoreceptors respond to visible light Ultraviolet receptors respond to ultraviolet radiation Electroreceptors respond to electric fields Ampullae of Lorenzini respond to electric fields, salinity, and to temperature, but function primarily as electroreceptors Hydroreceptors respond to changes in humidity Magnetoreceptors respond to magnetic fields Mechanoreceptors respond to mechanical stress or mechanical strain Nociceptors respond to damage, or threat of damage, to body tissues, leading (often but not always) to pain perception Osmoreceptors respond to the osmolarity of fluids (such as in the hypothalamus) Proprioceptors provide the sense of position Thermoreceptors respond to temperature, either heat, cold or both Sensory receptors can be classified by location: Cutaneous receptors are sensory receptors found in the dermis or epidermis.