A cross section of a bundle of nerve fibers. Axons (orange) are wrapped in myelin (purple); an extension of the membrane of glial cells. Myelin has high lipid content, and acts to insulate the axons, causing them to transmit nerve impulses much faster.
17 Things you should know about DNA (Infographic). It's the basic building block of all life but what do you really know about it? See how you compare to other humans and crack the genetic code with this informative infographic.