- Afferent nerve
nervous system, afferent neurons--otherwise known as sensory or receptor neurons--carry nerve impulses from receptors or sense organs "toward" the central nervous system. This is the case vice versa as well. 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 sensationin the brain only after information about the stimulus travels there via afferent nerve pathways. Afferent neurons are pseudounipolar neurons, that have a single long dendriteand 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 afferent nerves. Just outside the spinal cord, thousands of afferent neuronal cell bodies are aggregated in a swelling in the dorsal rootknown as the dorsal root ganglion. (See efferent nerve.)
Etymology and mnemonics
Afferent is derived from
Latinparticiple "afferentem" ("af- = ad-" : to + "ferre" : bear, carry), meaning carrying into."Ad" and "ex" give an easy mnemonic devicefor remembering the relationship between "afferent" and "efferent" : "afferent connection arrives" and an "efferent connection exits". [MedicalMnemonics|3502|3463|367|115]
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