In the<unk> us system,<unk>  neurons--otherwise known as sensory or receptor neurons--carry<unk>  impulses from receptors or sense organs toward the central<unk> us system.  This is the case vice versa as well. This term can also be used to describe relative connections between structures.<unk>  neurons communicate with specialized interneurons. (The opposite activity of direction or flow is<unk> .)
In the<unk> us system there is a "closed loop" system of sensation, decision, and reactions. This process is carried out through the activity of<unk>  neurons, interneurons, and<unk>  neurons.
A touch or painful stimulus, for example, creates a sensation in the brain only after information about the stimulus travels there via<unk>  pathways.<unk>  neurons are pseudounipolar neurons, that have a single long dendrite and a short axon, and a smooth and rounded cell body. The dendrite is structurally and functionally similar to an axon, and is myelinated; it is these axon-like dendrites that make up the<unk> s. Just outside the spinal cord, thousands of<unk>  neuronal cell bodies are aggregated in a swelling in the dorsal root known as the dorsal root ganglion. (See<unk> .)
Afferent nerve
Efferent nerve
Free nerve ending
Postganglionic fibers
Nerve
Nociceptor
Lumbar nerves
Upper motor neuron