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Most nerve fibers are surrounded by an insulating, fatty sheath called myelin, which acts to speed up impulses. The myelin sheath contains periodic breaks called nodes of Ranvier.
By jumping from node to node, the impulse can travel much more quickly than if it had to travel along the entire length of the nerve fiber. Myelinated nerves can transmit a signal at speeds as high as 100 meters per second. If the myelin sheath surrounding nerve fibers is damaged or destroyed, transmission of nerve impulses is slowed or blocked. The impulse now has to flow continuously along the whole nerve fiber -- a process that is much slower than jumping from node to node. Loss of myelin can also lead to 'short-circuiting' of nerve impulses.
An area where myelin has been destroyed is called a lesion or plaque. This slowing and 'short-circuiting' of nerve impulses by lesions leads to a variety of symptoms related to nervous system activity. Symptoms can include sensory impairment, such as blurred vision, difficulties in controlling movement, and problems with bodily functions, such as failure to control urination. Demyelinating disease may result in vision or hearing loss, headaches, seizures, muscle spasms and weakness, loss of coordination, paralysis, and loss of sensation.
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What facilitates the rate of myelination?
The rate of myelination is facilitated by several factors. One important factor is the activity of oligodendrocytes, the cells responsible for producing myelin in the CNS. Another factor is the presence of axonal signals that trigger oligodendrocyte differentiation and myelination. Additionally, the level of neuronal activity and electrical impulses can also influence the rate of myelination.
What are swan cells?
Responsible for myelination of neurons.
In what part of the brain does myelination occur last?
forebrain
What does gray matter lack that white matter has?
Myelination
What structure is responsible for myelination of the nerve fibers?
In the peripheral nervous system the cell that myelinates an axon is called a Schwann cell. In the central nervous system myelination is carried out by oligodendrocytes.
A factor that determines the rate of impulse propagation or conduction velocity along an axon?
The speed at which neural impulses are transmitted. Diameter of the axon Degree of myelination of the axon
A process called myelination increases how fast you process information?
True
Is myelination of the nerve fibers in the Central Nervous System the job of the oligodendrocyte?
True
Does the the autonomic nervous system typically have thin fibers with little or no myelination?
yes.
What is the process by which individual axons are insulated with fatty sheaths to enhance efficiency?
Myelination is that process.
Which two characteristics of axons increases the speed of nerve impulse?
diameter and presence of myelination.....
What are oligodendrocytes responsible for?
myelination of the axons and the dendrites are responsible for connection between the cell body and myelin
