This change in membrane potential will passively spread along the dendrite, but becomes weaker with distance without an action potential. Synaptic activity causes local changes in the electrical potential across the plasma membrane of the dendrite. Most inhibitory synapses directly contact the dendritic shaft. Excitatory synapses terminate on dendritic spines, tiny protrusions from the dendrite with a high density of neurotransmitter receptors. The dendrite of a large pyramidal cell receives signals from about 30,000 presynaptic neurons. Dendrites provide an enlarged surface area to receive signals from axon terminals of other neurons. Typically, axons transmit electrochemical signals and dendrites receive the electrochemical signals, although some types of neurons in certain species lack specialized axons and transmit signals via their dendrites. Dendrites often taper off in shape and are shorter, while axons tend to maintain a constant radius and can be very long. Axons can be distinguished from dendrites by several features including shape, length, and function. ĭendrites are one of two types of protoplasmic protrusions that extrude from the cell body of a neuron, the other type being an axon. Structure and function The extensive dendritic tree of two hippocampal pyramidal neurons (magenta) with all incoming synapses genetically labeled (green spots). Electrical stimulation is transmitted onto dendrites by upstream neurons (usually via their axons) via synapses which are located at various points throughout the dendritic tree.ĭendrites play a critical role in integrating these synaptic inputs and in determining the extent to which action potentials are produced by the neuron. Please see for interactive version.Ī dendrite (from Greek δένδρον déndron, "tree") or dendron is a branched protoplasmic extension of a nerve cell that propagates the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project. The dendrites receive a signal, the axon hillock funnels the signal to the initial segment and the initial segment triggers the activity (action potential) that is sent along the axon towards the synapse. Synapses allow neurons to activate other neurons. Schwann cells make activity move faster down axon. The neuron contains dendrites that receives information, a cell body called the soma, and an axon that sends information. For other uses, see Dendrite (disambiguation). This article is about neuronal dendrites in biology.
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