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 is an English vocabulary word for a small lustrous gemstone known as the pearl. In its natural state, a pearl is really an accident of nature. It is shaped by a mollusk (such as an oyster) through the secretion of calcium carbonate which forms around some irritant that gains access inside its shell (such as a parasite or grain of sand). The mollusk produces a pearl as a way of protecting itself from the foreign substance.