Afferent neurons' somas are located in the ganglia of the peripheral nervous system, and the axons of these cells travel from ganglion to ganglion and lead back to the spinal cord.
Medical Definition of SENSORY NEURON. : a neuron that transmits nerve impulses from a sense organ towards the central nervous system—compare interneuron, motor neuron.  Afferent neurons' somas are located in the ganglia of the peripheral nervous system, and the axons of these cells travel from ganglion to ganglion and lead back to the spinal cord. The majority of these are unipolar neurons in that they have a single axon leaving the cell body and is sent towards the sensory organ. The opposite direction of neural activity is efferent conduction. In the nervous system there is a closed loop system of sensation, decision, and reactions. This process is carried out through the activity of afferent neurons (sensory neurons), interneurons, and efferent neurons (motor neurons). Efferent Neurons (also known as efferent nerve fibers) are conducting cells that carry information from the central nervous system (the brain and spinal cord) to muscles and organs throughout the body.  Afferent neurons (also known as sensory neurons or afferent nerve fibers) are pathways that carry sensory information from the body to the central nervous system (the brain and spinal cord).  From Wikipedia, the free encyclopedia. Sensory neurons are nerve cells that transmit sensory information (sight, sound, feeling, etc.). They are activated by sensory input, and send projections to other elements of the nervous system, ultimately conveying sensory information to the brain or spinal cord. The somatic sensory system includes the sensations of touch, pressure, vibration, limb position, heat, cold, and pain. The cell bodies of somatic sensory afferent fibers lie in ganglia throughout the spine. These neurons are responsible for relaying information about the body to the central nervous system. (April 2014). In the peripheral nervous system, an afferent nerve fiber is the nerve fiber (axon) of an afferent neuron (sensory neuron). It is a long process (projection) extending far from the nerve cell body that carries nerve impulses from sensory receptors or sense organs toward the central nervous system. The opposite direction of neural activity is efferent conduction. In the nervous system there is a closed loop system of sensation, decision, and reactions. This process is carried out through the activity of afferent neurons (sensory neurons), interneurons, and efferent neurons (motor neurons). Afferent nerve. Definition. noun, plural: afferent nerves. The type of nerve that carries sensory nerve impulses from the periphery towards the central nervous system. Supplement. The peripheral nervous system of vertebrates has two main types of nerves. These are the efferent nerves and the afferent nerves Noun. 1. afferent neuron-a neuron conducting impulses inwards to the brain or spinal cord. sensory neuron. nerve cell, neuron-a cell that is specialized to conduct nerve impulses. afferent, afferent nerve, sensory nerve-a nerve that passes impulses from receptors toward or to the central nervous system. 
http://www.merriam-webster.com/medical/sensory%20neuron https://en.wikipedia.org/wiki/Afferent_nerve_fiber http://www.alleydog.com/glossary/definition.php?term=Efferent%20Neurons http://www.alleydog.com/glossary/definition.php?term=Afferent%20Neurons https://en.wikipedia.org/wiki/Sensory_neuron https://en.wikipedia.org/wiki/Afferent_nerve_fiber http://www.biology-online.org/dictionary/Afferent_nerve http://www.thefreedictionary.com/afferent+neuron
afferent neuron definition