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.
pearl1. 1  a smooth, rounded bead formed within the shells of certain mollusks and composed of the mineral aragonite or calcite in a matrix, deposited in concentric layers as a protective coating around an irritating foreign object: valued as a gem when lustrous and finely colored. Compare cultured pearl.