Afferent nerve
In the
nervous system,
afferent neuronscarry
nerve impulses from
receptors or sense organs
toward the
central nervous system. This term can also be used to describe relative connections between structures.
Afferent neurons communicate with specialized
interneurons. The opposite activity of direction or flow is
efferent.
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, interneurons, and efferent neurons.
A touch or
painful
stimulus, for example, creates a
sensation in the brain only after information about the stimulus travels there via afferent nerve pathways. The structure of an afferent neuron contains a single long
dendrite and a short
axon; the shape of the
cell body of an afferent neuron is smooth and rounded. Just outside the
spinal cord, thousands of afferent neuronal cell bodies are aggregated in a swelling in the
dorsal root known as the
dorsal root ganglion. (See
efferent nerve)
An easy
mnemonic device for remembering the relationship between
afferent and
efferent is that an
afferent connection
arrives and an
efferent connection
exits.
*
Sensory nerves*
Sensory neuron*
Efferent nerve*
Interneuron*
