For the crystal, see Dendrite (crystal).
In biology, a dendrite is a slender, typically branched projection of a nerve cell, or "neuron," which conducts the electrical stimulation received from other cells to the body or soma of the cell from which it projects. This stimulation arrives through synapses, which typically are located near the tips of the dendrites and away from the soma.
Dendrites were once believed to merely convey stimulation passively, without action potentials and without activation of voltage-gated ion channels. In such dendrites the voltage change that results from stimulation at a synapse may extend both towards and away from the soma. In other dendrites, voltage-gated channels help propagate excitatory synaptic stimulation whether or not an action potential is present. This propagation is efficient only toward the soma due to an uneven distribution of channels along such dendrites.
Scientists have shown that action potentials do propagate back into the dendrites once initiated in the axon in most neurons. This backpropagating action potential is mediated by the activation of voltage-gated ion channels and can interact with synaptic input to alter the synaptic activity.
The structure and branching of a neuron's dendrites strongly influences how it integrates the input from many others, particularly those that input only weakly (more at synapse). This integration is in aspects "temporal" -- involving the summation of stimuli that arrive in rapid succession -- as well as "spatial" -- entailing the aggregation of excitatory and inhibitory inputs from separate branches or "arbors."
The term "dendrite" comes from the Greek word dendron, meaning "tree".
See also: dendritic spine