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neuron


neuron

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Structure of a neuron. Dendrites, usually branching fibres, receive and conduct impulses to the …—© Merriam-Webster Inc.

Any of the cells of the nervous system. Sensory neurons relay information from sense organs, motor neurons carry impulses to muscles and glands, and interneurons transmit impulses between sensory and motor neurons. A typical neuron consists of dendrites (fibres that receive stimuli and conduct them inward), a cell body (a nucleated body that receives input from dendrites), and an axon (a fibre that conducts the nerve impulse from the cell body outward to the axon terminals). Both axons and dendrites may be referred to as nerve fibres. Impulses are relayed by neurotransmitter chemicals released by the axon terminals across the synapses (junctions between neurons or between a neuron and an effector cell, such as a muscle cell) or, in some cases, pass directly from one neuron to the next. Large axons are insulated by a myelin sheath formed by fatty cells called Schwann cells. Bundles of fibres from neurons held together by connective tissue form nerves.

Variants of NEURON

neuron or nerve cell

This entry comes from Encyclopædia Britannica Concise.
For the full entry on neuron, visit Britannica.com.

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