Another example of a synthesis reaction is the formation of sodium chloride (table salt). Because of the very high reactivities of sodium metal and chlorine gas, this reaction releases a tremendous amount of heat and light energy.
Schwann cells make myelin in the peripheral nervous system (PNS: nerves) and oligodendrocytes in the central nervous system (CNS: brain and spinal cord). In the PNS, one Schwann cell forms a single myelin sheath (Figure 1A).
Schwann cells: these cells provide the myelin that covers neurons in the peripheral nervous system. Larger neurons are covered in a myelin sheath. Myelin is high in lipid and serves the same purpose as insulation around electrical wires.Myelinated axons conduct nerve impulses faster.hese cells form the substance of the brain, spinal cord, and peripheral nervous system. The brain is composed of the basic units of the cerebral hemispheres, brainstem, and cerebellum. The cerebral hemispheres can be further categorized by structure and function.