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).
1 This cell, which is found primarily in the marginal layer, forms myelin sheaths around the ascending and descending axons in the marginal layer. 2  In the second half of development, a third type of supporting cell, the microglial cell, appears in the CNS. 3  This highly phagocytic cell type is derived from mesenchyme.