Medium spiny neuron

Neuron

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• published: 15 Jul 2014
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A neuron (/ˈnjʊərɒn/ NYEWR-on or /ˈnʊərɒn/ NEWR-on; also known as a neurone or nerve cell) is an electrically excitable cell that processes and transmits information through electrical and chemical signals. These signals between neurons occur via synapses, specialized connections with other cells. Neurons can connect to each other to form neural networks. Neurons are the core components of the nervous system, which includes the brain, spinal cord and the ganglia of the peripheral nervous system (PNS) which comprises the central nervous system (CNS). Specialized types of neurons include: sensory neurons which respond to touch, sound, light and all other stimuli affecting the cells of the sensory organs, that then send signals to the spinal cord and brain; motor neurons that receive signals from the brain and spinal cord, to cause muscle contractions, and affect glandular outputs, and interneurons which connect neurons to other neurons within the same region of the brain or spinal cord, in neural networks. A typical neuron possesses a cell body (soma), dendrites, and an axon. The term neurite is used to describe either a dendrite or an axon, particularly in its undifferentiated stage. Dendrites are thin structures that arise from the cell body, often extending for hundreds of micrometres and branching multiple times, giving rise to a complex "dendritic tree". An axon is a special cellular extension that arises from the cell body at a site called the axon hillock and travels for a distance, as far as 1 meter in humans or even more in other species. The cell body of a neuron frequently gives rise to multiple dendrites, but never to more than one axon, although the axon may branch hundreds of times before it terminates. At the majority of synapses, signals are sent from the axon of one neuron to a dendrite of another. There are, however, many exceptions to these rules: neurons that lack dendrites, neurons that have no axon, synapses that connect an axon to another axon or a dendrite to another dendrite, etc. This video is targeted to blind users. Attribution: Article text available under CC-BY-SA Creative Commons image source in video