Navigation Links
Axon


An axon, or "nerve fiber," is a long slender projection of a nerve cell, or "neuron," which conducts electrical impulses away from the neuron's cell body or soma. Axons are in effect the primary transmission lines of the nervous system, and as bundles they help make up nerves. Individual axons are microscopic in diameter--typically about one micrometre across-- but may extend to macroscopic lengths. The longest axons in the human body, for example, are those of the sciatic nerve, which run from the base of the spine to the big toe of each foot. These single-cell fibers may extend a metre or even longer.

In vertebrates generally, the axons of many neurons are sheathed in myelin, which is formed by either of two types of glial cells: Schwann cells ensheathing peripheral neurons and oligodendrocytes insulating those of the central nervous system. Along myelinated nerve fibers, gaps in the sheath known as nodes of Ranvier occur at evenly spaced intervals, enabling an especially rapid mode of electrical impulse propagation called saltation.

The axons of some neurons branch to form axon collaterals , along which the bifurcated impulse travels simultaneously to signal more than one other cell.

History

Some of the first intracellular recordings in a nervous system were made in the late 1930's by K. Cole and H. Curtis. Alan Hodgkin and Andrew Huxley also employed the squid axon (1939) and by 1952 they had obtained a full quantitative description of the ionic basis of the action potential. Hodgkin and Huxley were awarded jointly the Nobel Prize for this work in 1963.

See also

http://www.sfn.org/wrensite/projects/patch_clamp/index.htm


'"/>


(Date:11/6/2014)... groundbreaking paper from a team of Florida State University ... plants could adapt to and survive environmental swings such ... the latest issue of the journal The Plant ... of DNA and proteins) is organized in a cell ... genes are turned on and others are turned off. ...
(Date:11/6/2014)... Except when that predator runs so fast that it essentially ... is the fastest creature on Earth. Some of these half-inch-long ... five miles per hour). The fastest human can do about ... tiger beetle, a person would have to hit 480 miles ... At peak speeds, everything becomes a blur. They can,t gather ...
(Date:11/5/2014)... Fidel Santamaria, associate professor of biology in the ... researchers in the nation selected to receive a ... Grant for Exploratory Research (EAGER). The funding supports ... support researchers to create new technology that will ... Santamaria, complex behaviors in neuroscience are broken into ...
Breaking Biology News(10 mins):Maize analysis yields whole new world of genetic science 2The tiger beetle: Too fast to see 2UTSA biology professor awarded $300,000 NSF grant for brain research 2UTSA biology professor awarded $300,000 NSF grant for brain research 3
... Bioengineers have taken a small step toward improving physical recovery ... how limb motion is encoded in the nervous system plays ... Published in the November 25, 2009 issue of ... responsible for motor learning may help scientists design rehabilitation protocols ...
... You can conserve fish and eat them too, according ... with a team of experts. "We found that ... fish, you can put the Marine Protected Areas in ... fisheries more profitable," said Christopher Costello, economist and professor ...
... the University of Sheffield have scooped an international award in ... make the production of alternative biofuels more energy efficient. ... use in the production of alternative renewable fuels, to replace ... biofuels currently requires vast amounts of power and when the ...
Cached Biology News:Observation about how nervous system learns and encodes motion could improve stroke recovery 2Observation about how nervous system learns and encodes motion could improve stroke recovery 3Environmentalists and fishing community can both win, say experts 2Scientists' breakthrough in production of biofuels 2
Other biology definitionOther Tags