Dendrite
Say it: DEN-dryt
A dendrite is one of the short, branching extensions of a neuron that receive signals from other cells and carry them toward the cell body.
Also: dendrites
Definition
What is a dendrite?
A dendrite is a branched extension of a neuron's cell body that serves as its main receiving surface. Most neurons have many dendrites, which spread out like the limbs of a tree and form synapses with the axon terminals of other neurons. Many are studded with dendritic spines, tiny knobs that add surface area and each host a synapse.
When a neurotransmitter binds receptors on a dendrite, ion channels open and the membrane voltage shifts a little. This graded change can be excitatory, nudging the cell toward firing, or inhibitory, pushing it away. Unlike action potentials, these signals weaken as they spread, so the neuron adds up the many inputs arriving across its dendrites and over time. Only if the combined effect reaches threshold at the axon hillock does the neuron fire.
The size and branching of a neuron's dendrites help set how many inputs it can combine; Purkinje cells of the cerebellum, for example, have huge, fan-shaped dendritic trees. Lasting changes in the strength of synapses on dendrites, such as long-term potentiation, are thought to be a basis of learning and memory.
Word parts
Where does the word “dendrite” come from?
- dendr-
- treeGreek dendron
- -ite
- a part or thing belonging toGreek -ites
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Terms that go with it
- NeuronA neuron is a nerve cell, the basic signaling unit of the nervous system, which receives information and passes it on as electrical and chemical signals.
- AxonAn axon is the single long projection of a neuron that carries electrical impulses away from the cell body toward other neurons, muscles or glands.
- SynapseA synapse is the junction where a neuron passes a signal to another cell, usually by releasing a neurotransmitter across a narrow gap.
- NeurotransmitterA neurotransmitter is a chemical messenger that a neuron releases at a synapse to excite or inhibit a target neuron, muscle cell or gland cell.
- ReceptorA receptor is a protein, on a cell's surface or inside it, that binds a specific signaling molecule and triggers a response in the cell.
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Checked against
Written for biofideX in plain words, after checking these references:
- OpenStax Anatomy and Physiology 2e, 12.2 Nervous Tissue
- OpenStax Biology 2e, 35.1 Neurons and Glial Cells
- OpenStax Biology 2e, 35.2 How Neurons Communicate
- NCBI MeSH: Dendrites
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