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Nerve impulse is an electrical current, which flows across the axons. So most of the neurons are surrounded by myelin sheath. This sheath gives insulation to the axons. Brain can not function without this insulation.
Wiki User
∙ 9y ago
Wiki User
∙ 9y agoNot all axons are covered by a myelin sheath. Only those found outside the central nervous system are.
The sheath acts very much like the covering on a wire that you would plug into the wall.
It also is not in a continuous layer but is found in ring like areas. These allow the impulses to travel more rapidly.
Those that have this sheath produce what is called white matter, the uncovered ones are called gray matter.
Wiki User
∙ 12y agoinsulation & prevents loss or disruption of signal
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What surrounds the axon?
Some but not all axons are covered with Schwann's cells which are filled with myelin.
What are specialized coverings of the axon?
Myelin covers the axon to protect it and help messages travel faster. Two types of cells produce myelin, the oligodendrocytes in the CNS and Schwann cells in the PNS.
What is the fatty substance that speeds up transmission of impulses and surrounds the axon of a neuron?
The fatty tissue surrounding the axon of a neuron is called myelin.
What is the function of neuroglial cells in nervous tissue?
Glial cells provide protection and support for the neurons. This is why they are called "the supporting cells" of the nervous system. They act as insulation and provide structure to surrounding neurons. Some protect the neurons from disease. Some can provide the insulation (white matter) along their axons, through differing mechanisms depending on the types. Astrocytes help regulate chemical environment and blood flow, schwann cells provide myelin sheaths (insulation) in the PNS, oligodendrocytes provide myelin sheaths in the CNS, and microglia act similarly to certain white blood cells.
The axons of some neurons have an insulating coating called?
This is called myelin or myelin sheath. It's made mainly from fat with a few proteins in it, and is produced by oligodendrocyte cells in the CNS and schwann cells in the peripheral nervous system. It speeds up nerve signalling by allowing action potentials (the electric currents that make up nerve impulses) to skip between the gaps in the myelin (nodes of ranvier). In unmyelinated axons, sodium and potassium channels have to create the voltage differences at every single step along the nerve. (Say for example 100 times per nerve). Myelinated neurones only need to create these voltage differences at the nodes of ranvier (where sodium and potassium ion channels are located on myelinated neurones) Say for example there are 10 nodes of ranvier on a myelinated axon. The unmyelinated axon must create this voltage difference 10 times more frequently than the myelinated axon, hence the nerve impulse travels 10 times faster in a myelinated axon. (Based on the random numbers I used. In real life the numbers may be wildly different, but they still work in this way).
Sheaths of what cells often enclose the axons outside the brain and spinal cord?
Schwann cells make the myelin sheath that encloses some axons
Is it becaue they are large with thick myelin sheaths?
Your question is not complete. There is not enough information. What are you referring to as "they". Some nerve fibers have thick myelin sheaths and some don't.
Material that provides insulation for some axons?
You may be referring to the myelin .
What surrounds the axon?
Some but not all axons are covered with Schwann's cells which are filled with myelin.
What are the functions of oligodendrocytes?
They insulate axons by producing myelin sheathing in the neural network of some vertebrates.
What are specialized coverings of the axon?
Myelin covers the axon to protect it and help messages travel faster. Two types of cells produce myelin, the oligodendrocytes in the CNS and Schwann cells in the PNS.
What do nerves do for a muscle?
There are things called neurons that have parts called dendrites and axons. The dendrites of a neuron are branching, tubelike extensions of the cell body that form a pattern resembling the limbs of a tree. Most neuron cell bodies have about six main dendrites, each of which is two or three times as thick as the axon of the cell. The distance between the cell body and the tips of the dendrites is about 0.5 millimetre. Dendrites are specialized structures for receiving impulses they are like mailboxes, mostly from the axon of another neuron. Dendrites and axons do not quite touch each other. In almost all cases, they are separated by an extremely narrow space called the synaptic cleft, over which nerve impulses are transmitted. These places where one neuron communicates with another are called synapses.The axon, also called the nerve fibre, is a tubelike extension of a neuron cell body. The axon is specialized to carry messages. An axon of one neuron may have enough branches to make contact with as many as 1,000 other neurons. Most axons in the central nervous system are less than 1 millimetre long. However, many axons in the peripheral nervous system are longer, and some are much longer. For example, the axons that extend from the spinal cord to the muscles in the feet may be 75 to 100 centimetres long. The structures commonly called nerves are actually bundles of axons lying next to one another in a cordlike formation. Nerves can be made up of the axons of motor neurons or sensory neurons, or of both. Some axons are covered by a sheath of a white, fatty substance called myelin. The myelin increases the speed of impulses along the axons. Myelin also causes the distinction between the grey matter and white matter in the nervous system. Grey matter consists largely of unmyelinated axons (axons without myelin sheaths) and neuron cell bodies. White matter is made up mostly of axons that have white sheaths of myelin. Myelin is formed in the peripheral nervous system by Schwann cells, which are special supporting cells that surround the axons. In the central nervous system, supporting cells called glia produce myelin.There are things called neurons that have parts called dendrites and axons. The dendrites of a neuron are branching, tubelike extensions of the cell body that form a pattern resembling the limbs of a tree. Most neuron cell bodies have about six main dendrites, each of which is two or three times as thick as the axon of the cell. The distance between the cell body and the tips of the dendrites is about 0.5 millimetre. Dendrites are specialized structures for receiving impulses they are like mailboxes, mostly from the axon of another neuron. Dendrites and axons do not quite touch each other. In almost all cases, they are separated by an extremely narrow space called the synaptic cleft, over which nerve impulses are transmitted. These places where one neuron communicates with another are called synapses.The axon, also called the nerve fibre, is a tubelike extension of a neuron cell body. The axon is specialized to carry messages. An axon of one neuron may have enough branches to make contact with as many as 1,000 other neurons. Most axons in the central nervous system are less than 1 millimetre long. However, many axons in the peripheral nervous system are longer, and some are much longer. For example, the axons that extend from the spinal cord to the muscles in the feet may be 75 to 100 centimetres long. The structures commonly called nerves are actually bundles of axons lying next to one another in a cordlike formation. Nerves can be made up of the axons of motor neurons or sensory neurons, or of both. Some axons are covered by a sheath of a white, fatty substance called myelin. The myelin increases the speed of impulses along the axons. Myelin also causes the distinction between the grey matter and white matter in the nervous system. Grey matter consists largely of unmyelinated axons (axons without myelin sheaths) and neuron cell bodies. White matter is made up mostly of axons that have white sheaths of myelin. Myelin is formed in the peripheral nervous system by Schwann cells, which are special supporting cells that surround the axons. In the central nervous system, supporting cells called glia produce myelin.
What is the fatty substance that speeds up transmission of impulses and surrounds the axon of a neuron?
The fatty tissue surrounding the axon of a neuron is called myelin.
These cover the axonin order to make nerve signals faster?
Some axons have an insulating coating, called the fatty myelin sheath, to make signals travel faster.
What is the function of neuroglial cells in nervous tissue?
Glial cells provide protection and support for the neurons. This is why they are called "the supporting cells" of the nervous system. They act as insulation and provide structure to surrounding neurons. Some protect the neurons from disease. Some can provide the insulation (white matter) along their axons, through differing mechanisms depending on the types. Astrocytes help regulate chemical environment and blood flow, schwann cells provide myelin sheaths (insulation) in the PNS, oligodendrocytes provide myelin sheaths in the CNS, and microglia act similarly to certain white blood cells.
What is the function of the axon in a nerve cell?
The axon is the elongated fiber that extends from the cell body to the terminal endings and transmits the neural signal. The larger the axon, the faster it transmits information. Some axons are covered with a fatty substance called myelin that acts as an insulator. These myelinated axons transmit information much faster than other neurons.
The main component of the myelin sheath is?
Myelin is composed of about 80% lipid and about 20% protein. Some of the proteins that make up myelin are myelin basic protein (MBP),myelin oligodendrocyte glycoprotein (MOG), and proteolipid protein (PLP). Myelin is made up primarily of a glycolipid calledgalactocerebroside. The intertwining of the hydrocarbon chains of sphingomyelin serve to strengthen the myelin sheath.There are quite a few disease (multiple sclerosis, optic neuritis, transverse myelitis..) involved in the destruction of the axon myelin sheath also known as myelin sheath.http://en.wikipedia.org/wiki/Myelin
