Dendrites

Definition

Branched, tapering cytoplasmic processes extending from the soma (cell body) of a neuron that receive electrochemical signals from upstream neurons via synapses and propagate these stimuli toward the cell body. In arthropods, dendrites are typically unmyelinated and often associated with specialized sensory structures; for example, the dendritic arbor of a mechanosensory hair sensillum in insects terminates within the shaft, while chemosensory neurons may bear multiple dendritic branches within a single sensillum to increase receptive surface area.

Etymology

From Greek dendron, 'tree', referring to the characteristic branching morphology.

Example

In the Johnston's organ of Drosophila and other insects, the dendrites of chordotonal sensory neurons attach to the cuticular structures that detect sound-induced vibrations, with their mechanical displacement generating receptor potentials.

Synonyms

• Dendrons

Related Terms

• axon
• synapse
• sensillum
• chordotonal organ
• Soma
• Neuropil
• Mechanoreceptor

Usage Notes

Distinguish from 'dendritic' mineral crystal formations or the taxon Dendrites (a hemipteran genus). In arthropod neurobiology, dendrites are strictly afferent (input) structures, whereas axons convey output; this polarity is less absolute in some central neurons with dendrodendritic synapses. The term is sometimes used loosely for any branched cellular process, but precise usage reserves it for neuronal receptive processes.