What is the the Average speed of a Neuron? And does anybody know if Neurons travel faster in certain locations, for example: Do Neurons travel faster in the brain, spine, muscle tissues, etc.
Any information would great,
Thanks for your time!!
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Neurons don't travel, the impulses they transmit do. As a simple analogy, a neuron is like an electric cord: it stays still but an electric current flows through it. In the same way, a neuron stays still and electrical potentials (graded potentials and an action potential) move along its membrane from source to destination. Usually, one is most interested in the action potential that travels along the axon of a neuron.
The speed with which an action potential travels down an axon depends on several things, the two most important being whether or not the action is myelinated and the diameter of the axon.
1. Myelination: Many axons (especially in the brain) are myelinated. That means they have a sheath of myelin (a white, fatty substance) covering the length of axon, with some gaps (called nodes or Nodes of Ranvier) occurring every so often that expose the membrane so that the action potential can be regenerated. Myelination greatly increases the speed at which an action potential can travel down an axon because it can jump from one node to the next instead of having to travel every millimeter along the axon. It like the difference between walking heel-to-toe vs taking long strides are you run.
2. Axon diameter. In an electrical conductor, the greater the diameter of the conductor the less the resistance to the flow of the current through the conductor is. The same general principle applies to axons.
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"Axons are classified into three groups according to the relationship among the diameter, myelination, and propagation speed.
1. Type A fibers are the largest axons, with diameters ranging from 4 to 20 [micro]meters. These are myelinated axons that carry action potentials at speeds of up to 140 meters per second, or over 300 mph.
2. Type B fibers are smaller myelinated axons, with diameters of 2 - 4 [mciro]meters. Their propagation speeds average around 18 meters per second, or roughly 40 mph.
3. Type C fibers are unmyelinated and less than 2 [micro]meters in diameter. These axons propagate action potentials at the leisurely pace of 1 meter per second, or a mere 2 mph.”
(Fundamentals of Anatomy & Physiology: Sixth Edition, Frederic H. Martini, Benjamin Cummings, 2004, p409)
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PS: Another factor in how fast impulses are conducted through the nervous system is the type and number of synpases (junctions between two adjacent neurons). Electrical synapses are faster than chemical synapses, but far fewer. In a chemical synpase, there is a delay as the electrical action potential is converted into a chemical signal that must diffuse across a gap between the two neurons, and then reconverted into an electrical signal.
In fact, the existence of synapses was inferred by the simple fact that the impulses traveled faster in the non-brain regions of the nervous system than in the brain itself. Clearly, something was slowing down the impulses in the brain, and one scientist proposed that there were gaps between neurons that the signals had to cross, and that there were many of them in the brain. Turns out, he was right.
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How fast do Neurons travel?
What is the the Average speed of a Neuron? And does anybody know if Neurons travel faster in certain locations, for example: Do Neurons travel faster in the brain, spine, muscle tissues, etc.
Any information would great,
Thanks for your time!!
Human body is made up of trillions of cells. The human brain is an extraordinary organ which cannot function without the neurons. Neurons are the nerve cells and billions of these cells make up our brain. They are of different shapes and sizes. The central nervous system consists of the brain and the spinal cord. This system plays a vital role in regulating our actions like pulling out our hands when we touch very hot objects and so on.
Their structure consists of three basic parts – cell body (soma), dendrites (nerve endings) and axon. Cell body is the main part containing the nucleus. If the body dies, the neuron dies. Dendrites or nerve endings make connections with other cells so as to enable communication with the other neurons. Axons are long wire like projections that carries signals along the length of the cell. They can be up to 1 mm in diameter.
Neurons are of three types – sensory, motor and inter neurons. Sensory neurons carry signals from other parts of the body to the brain while motor neurons carry signals from brain to other parts of the body. Interneuron connects multiple neurons within the brain and spinal cord.
Neurons gather electrochemical signals from all parts of body and transmit it to the brain. Electrochemical signals are electrical signals caused by chemicals. Sodium, potassium, chlorine, calcium are some of the chemicals present in our body. When it is not sending any signal, it is said to be at rest. When these chemicals get electrically charged they are called ions. Action is said to take place when these ions cross the neuron membrane.
Source(s):
Neurons do not travel. Action potentials (or nerve impulses) are propagated from one of the cell (closer to the dendrites, near the axon hillock) to the other (near the neurotransmitter terminals). The speed of transmission is dependent on the length of the axon and its target location and is increased with insulation (because of the myelin sheath).
myelin allows the AP to jump from node to node and therefore travels faster.