Neurons

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The nerve cell (neuron) is the basic structural and functional unit of the nervous system. Each neuron consists of a cell body which contains a large nucleus surrounded by cytoplasm and processes called dendrites and axons. These process are peculiar to neurons and are responsible for the conduction and transmission of neural information.

Conducting cells of the body

Neurons are the conducting cells of the nervous system. A typical neuron consists of a cell body, containing the nucleus and the surrounding [glossary term:] cytoplasm; several short radiating processes (called dendrites); and one long [glossary term:] process (called the axon), which terminates in twiglike branches and may have branches projecting along its course. In many ways, the cell body is similar to other types of cells. It has a nucleus with at least one nucleolus and contains many of the typical cytoplasmic organelles. It lacks [glossary term:] centrioles, however. Because centrioles function in cell division, the fact that neurons lack these organelles is consistent with the [glossary term:] amitotic nature of the cell.

Dendrites and Axons

An axon is a long, hair-like extension of a nerve cell that carries a message to another nerve cell.

Dendrites are thread-like extensions of the cytoplasm of a neuron that receive signals from other neurons. Typically, as in multipolar neurons, dendrites branch into treelike processes, but in unipolar and bipolar neurons, dendrites resemble axons.

Glial Cells

Glial (Neuroglial) cells do not conduct nerve impulses, but, instead, support, nourish, and protect the neurons. Glial cells are far more numerous than neurons and, unlike neurons, are capable of [glossary term:] mitosis.

How a neuron works

Neurons are unique because they can send information from the brain to the rest of the body. Your brain communicates with the rest of your body by sending messages from one neuron to the next and ultimately to the muscles and organs of the body. Neurons can also store information as memories.

Parts of a neuron

Typically, a neuron contains three important parts: a cell body that directs all activities of the neuron; dendrites (the part that looks like tree branches), which are short fibers that receive messages from other neurons and relay those messages to the cell body; and the axon, a long single fiber that transmits messages from the cell body to dendrites of other neurons. Every moment, messages are moving with amazing speed back and forth from neuron to neuron. As a matter of fact, scientists often compare the activity of neurons to the way electricity works.

Communication between neurons

A neuron communicates with other neurons at special places called synapses or synaptic clefts. To send a message, a neuron releases a chemical messenger, or neurotransmitter, into the synaptic cleft. From there, the neurotransmitter crosses the synapse and attaches to key sites called receptors on the next neuron in line. When neurotransmitters attach to these receptors, they cause changes inside the receiving neuron and the message is delivered.

External links

  • [The Life and Death of a Neuron Life and death of a neuron]


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