New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Axon

An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, that 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 meter or even longer.

In vertebrates, 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.

Related Stories
 


Health & Medicine News

June 17, 2026

Scientists have taken a surprising step toward unlocking regeneration in mammals, showing that the ability to rebuild complex body parts may not be lost after all—it may simply be switched off. Using a two-stage treatment, researchers redirected ...
A Rutgers study suggests GLP-1 drugs such as Ozempic and Wegovy may weaken the link between impulsive tendencies and violent behavior. The surprising finding hints that these medications could affect how people act on impulses, though researchers ...
Exposure to a common plastic chemical before and shortly after birth may have lasting effects on behavior. Researchers found that male rats exposed early in life to DEHP—a plasticizer used in products ranging from medical devices to toys—showed ...
A small clinical trial suggests that probiotics may offer a surprising mental health boost for older adults with depression. Seniors who took a daily probiotic alongside their regular antidepressant treatment experienced slightly greater ...
A minimally invasive treatment that blocks inflammation-driving blood vessels in the knee provided significant pain relief and improved function for osteoarthritis patients, with benefits lasting at least a year. The procedure was safe, highly ...
Scientists are beginning to explore a hidden world of thousands of food chemicals that go far beyond the nutrients listed on nutrition labels. This “nutritional dark matter” may hold the key to understanding disease risk, healthy aging, and why ...
Depression appears to change what children notice in the faces around them, but the effect depends on family history. Kids with a higher inherited risk became more focused on sadness, while lower-risk children lost some of their natural attention to ...
Diabetes and dementia appear to be closely intertwined, with each condition potentially influencing the other. Problems with insulin and glucose can affect the brain’s energy supply, increase inflammation, and damage blood vessels linked to memory ...
A new study found that chronic wasting disease can sometimes spread silently, with infectious prions present even in animals that show no symptoms. While there is no confirmed human risk, researchers ...
Many people prescribed GLP-1 drugs for type 2 diabetes (such as Victoza, Ozempic, or tirzepatide) stop taking them, but a surprising number later return to treatment. Researchers found that newer medications appear to keep patients on therapy ...
A large real-world study suggests semaglutide (Ozempic, Wegovy, Rybelsus) may offer an unexpected bonus for people with type 2 diabetes: stronger protection against bone fractures while delivering ...
Humans evolved to pay close attention to danger, but today that instinct is being overwhelmed by an endless supply of bad news from around the world. Researchers say the answer isn’t to stop following current events—it’s to build healthier ...

Latest Headlines

updated 12:56 pm ET