Most of the axons in the central nervous system are wrapped in myelin, a substance rich in lipids (fatty substances) and proteins. Like the coating around an electrical wire, myelin insulates and protects the axon and helps speed nerve transmission.
Potato/Semi Round Pearls. Potato pearls are some of the less expensive freshwater pearls to be found on the market, but their look is anything but cheap. You can purchase potato pearls in every color of the rainbow, and craft beautiful one of a kind creations for gifts and your own collection.
pearl. 1  a smooth, hard, usually white or bluish-gray body of varied but usually roundish shape that is an abnormal nacreous growth within the shell of some oysters and certain other bivalve mollusks and forms around a grain of sand, a parasite, or some other foreign object: it is used as a gem. 2  mother-of-pearl.