Efferent nerve

Efferent nerve

In the nervous system, efferent nerves – otherwise known as motor or effector neurons – carry nerve impulses "away" from the central nervous system to effectors such as muscles or glands (and also the ciliated cells of the inner ear). The term can also be used to describe relative connections between nervous structures (for example, a neuron's efferent synapse provides input to another neuron, and not vice-versa). The opposite activity of direction or flow is afferent.

The motor nerves are efferent nerves involved in muscular control. The cell body of the efferent neuron is found in the central nervous system where it is connected to a single, long axon and several short dendrites projecting out of the cell body itself. This axon then forms a neuromuscular junction with the effectors. The cell body of the motor neuron is satellite-shaped. The motor neuron is present in the grey matter of the spinal cord and medulla oblongata, and forms an electrochemical pathway to the effector organ or muscle.

Etymology and Mnemonics

Both afferent and efferent come from French, evolved from Latin (the basis of many terms in medicine and biology) for the terms, respectively, "ad ferens" (Latin verb "ferre": carry), meaning "carrying into", and "ex ferens", meaning "carrying away". "Ad" and "ex" give an easy mnemonic device for remembering the relationship between "afferent" and "efferent": "afferent connection arrives" and an "efferent connection exits". [MedicalMnemonics|3502|3463|367|115]

ee also

* Afferent nerve
* Motor nerve
* Interneuron
* General somatic efferent fibers
* General visceral efferent fibers

References

External links

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  • Efferent nerve fiber — Nerve: Efferent nerve fiber Latin neurofibrae efferentes Code TH H2.00.06.1.00016 In the nervous system, efferent nerves, otherwise known as motor or effector neurons, carry nerve impulses away from the central nervous system to eff …   Wikipedia

  • efferent nerve — noun a nerve that conveys impulses toward or to muscles or glands • Syn: ↑motor nerve, ↑efferent • Derivationally related forms: ↑efferent (for: ↑efferent) • Hypernyms: ↑ …   Useful english dictionary

  • efferent nerve — A nerve that conducts from a nerve center toward the periphery; the axon of a motor neuron that conducts impulses to the effectors …   Dictionary of invertebrate zoology

  • efferent nerve — any nerve that carries impulses from the central nervous system toward the periphery, as a motor nerve; cf. afferent n …   Medical dictionary

  • Nerve fiber — Latin neurofibra MeSH Nerve+Fibers Code TA A14.0.00.001 A nerve fiber is a threadlike extension of a nerve cell and consists of an axon …   Wikipedia

  • Efferent — is an anatomical term with the following meanings: *Conveying away from a center, for example the Efferent arterioles conveying blood away from the Bowman s capsule in the Kidney. Opposite to Afferent. *Something that so conducts, see Efferent… …   Wikipedia

  • efferent Physiology — [ ɛf(ə)r(ə)nt] adjective relating to or denoting the conduction of nerve impulses or blood outwards or away from something. The opposite of afferent. noun an efferent nerve fibre or blood vessel. Origin C19: from L. efferent , efferre carry out …   English new terms dictionary

  • efferent — [ef′ər ənt] adj. [< L efferens, prp. of efferre, to carry out < ex , out + ferre, BEAR1] Physiol. carrying away from a central part; specif., designating nerves that carry impulses away from a nerve center: opposed to AFFERENT n. an… …   English World dictionary

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  • efferent fibers — efferent nerve fibers 1. neurofibrae efferentes. 2. fibers or axons that are projecting away from a nucleus, using that nucleus as a reference point …   Medical dictionary

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