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).
Each neuron is made up of a cell body and an axon (the extension of the cell body that carries messages). Most of the axons in the central nervous system are wrapped in myelin, a substance rich in lipids (fatty substances) and proteins.NS myelin is produced by special cells called oligodendrocytes. PNS myelin is produced by Schwann cells. The two types of myelin are chemically different, but they both perform the same function â to promote efficient transmission of a nerve impulse along the axon.