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).
As we get older, we can continue to generate more myelin onto our axons, but it happens at a slower rate and requires more effort. Scientists believe that two non-neuron (or âglialâ) cells that exist in the brain play a role in creating new myelin. The first is a glial cell called an astrocyte.