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.
small cancerous lung tumor, I would just like to add that I don't mind the sales of cigarrettes, this is what people risk. The smarter generation shall live on, we don't have enough room on this floating rock to keep everyone.