Anatomy and PhysiologyArticle 12 / 20 /12How Nerve Signals Are Sent also shed light on how nerves developAround the Body at Varying Speeds before and after birth.as Electrical Impulses Professor Peter Brophy, Director of the University of Edinburghs Centre forOct. 11, 2012 — Scientists have proved a Neuroregeneration, said: "The study gives60-year-old theory about how nerve signals us greater insight into how the central andare sent around the body at varying speeds peripheral nervous systems work and whatas electrical impulses. happens after nerves become injured. We know that peripheral nerves have theResearchers tested how these signals are capacity to repair, but shorter lengths oftransmitted through nerve fibres, which insulation around the nerve fibres afterenables us to move and recognise sensations repair affect the speed with which impulsessuch as touch and smell. are sent around the body."The findings from the University of The researchers found that when the myelinEdinburgh have validated an idea first reached a certain length, the speed withproposed by Nobel laureate Sir Andrew which nerves impulses were conductedHuxley. reached a peak.It has been known for many years that an The study, carried out in mice, alsoinsulating layer -- known as myelin -- which confirmed that a protein -- periaxin -- playssurrounds nerve fibres is crucial in a key role in regulating the length of myelindetermining how quickly these signals are layers around nerve fibres.sent. Review Questions – Cornell FormatThis insulating myelin is interrupted atregular intervals along the nerve by gaps 1. According to the article, what havecalled nodes. scientists proved?Scientists, whose work was funded by the 2. What do signals transmitted throughWellcome Trust, have now proved that the nerve fibers allow us to do?longer the distance between nodes, thequicker the nerve fibres send signals down 3. What is the name of the insulating layerthe nerves. that allows nerve signals to be sent quickly throughout the body?The theory that the distance between thesegaps might affect the speed of electrical 4. What are the interruptions of thesignals was first proposed by Sir Andrew insulating layer at regular intervalsHuxley, who won the Nobel Prize in 1963 called?for his work on electrical signalling in thenervous system, and who died earlier this 5. Who was the first person to proposeyear. the theory on the speed of nerve impulses?The study, published in the journal CurrentBiology, will help provide insight into whathappens in people with nerve damage. It will
Anatomy and PhysiologyArticle 12 / 20 /12 6. What happens to the insulation of peripheral nerve fibers after injury? 7. What did researchers discover about the protein, periaxin?