Navigation Links

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.


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


(Date:10/29/2015)... MINNETONKA, Minn. , Oct. 29, 2015   ... that supports the entire spectrum of clinical research, is ... the Minnesota High Tech Association (MHTA) as one of ... in the "Software – Small and Growing" category. The ... and individuals who have shown superior technology innovation and ...
(Date:10/29/2015)... , Oct. 29, 2015 Daon, a global ... it has released a new version of its ... North America have already installed ... also includes a FIDO UAF certified server component ... preparing to activate FIDO features. These customers include some ...
(Date:10/29/2015)... BOSTON , Oct. 29, 2015  Connected health ... phenomena driving the explosion of technology-enabled health and wellness, ... his new book, The Internet of Healthy ... apps, sensors or smartphones even existed, Dr. Kvedar, vice ... model of health care delivery, moving care from the ...
Breaking Biology News(10 mins):
Other biology definition