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Myelin Sheath

A fatty covering that forms a protective sheath around nerve fibers and dramatically speeds the transmission of nerve signals.

PubMed Health Glossary
(Source: NIH - National Institute of General Medical Sciences)

Terms to know

Axons
Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.
Cell Body
The bulbous end of a neuron, containing the cell nucleus.
Cell Surface Extensions
Specialized structures of the cell that extend the cell membrane and project out from the cell surface.
Dendrites
A long, branching outgrowth or extension from a neuron, that carries electrical signals from synapses to the cell body.
Nerve Fibers
Slender processes of neurons, including the axons and their glial envelopes (myelin sheath). Nerve fibers conduct nerve impulses to and from the central nervous system.
Neurons (Nerve Cells)
A type of cell that receives and sends messages from the body to the brain and back to the body. The messages are sent by a weak electrical current. Also called nerve cell.
Neurotransmitters
A chemical that is made by nerve cells and used to communicate with other cells, including other nerve cells and muscle cells.
Oligodendrocyte
A cell that forms the myelin sheath (a layer that covers and protects nerve cells) in the brain and spinal cord.
Phospholipids
A lipid (fat) that contains phosphorus. Phospholipids are a major part of cell membranes.
Postsynaptic Membrane
Cell membranes associated with synapses.
Proteins
A molecule made up of amino acids. Proteins are needed for the body to function properly. They are the basis of body structures, such as skin and hair, and of other substances such as enzymes, cytokines, and antibodies.
Receptors
A molecule inside or on the surface of a cell that binds to a specific substance and causes a specific effect in the cell.
Schwann Cells
Schwann cells function to support neurons in the peripheral nervous system. Schwann cells wrap around axons to form the myelin sheath.
Synapses
The space between the end of a nerve cell and another cell. Nerve impulses are usually carried to the neighboring cell by chemicals called neurotransmitters, which are released by the nerve cell and are taken up by another cell on the other side of the synapse.
Synaptic Terminals (Axon Terminals)
An area at the end of an axon that contains neurotransmitters.

Terms to know

Axons
Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body....
Cell Body
The bulbous end of a neuron, containing the cell nucleus....
Cell Surface Extensions
Specialized structures of the cell that extend the cell membrane and project out from the cell surface....
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