Afferent nerve fiber


Afferent nerve fiber
Nerve: Afferent nerve fiber
Latin neurofibrae afferentes
Code TH H2.00.06.1.00015

In the nervous system, afferent neurons (otherwise known as sensory or receptor neurons), carry nerve impulses from receptors or sense organs towards 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. Afferent neurons are pseudounipolar neurons, that have a single long dendrite and a short axon[citation needed], 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 root known as the dorsal root ganglion.

Contents

Etymology and mnemonics

Afferent is derived from Latin participle afferentem (af- = ad- : to + ferre : bear, carry), meaning carrying into. Ad and ex give an easy mnemonic device for remembering the relationship between afferent and efferent : afferent connection arrives and an efferent connection exits.[1]

Another mnemonic device is SAME DAVE. Sensory Afferent Motor Efferent, Dorsal Afferent Ventral Efferent.

See also

References

  1. ^ Mnemonic at medicalmnemonics.com 3502 3463 367 115

External links


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