In the peripheral nervous system, the larger diameter axons are surrounded by a lipid-rich myelin sheath formed by the Schwann Cells.
Examine a cross section of a nerve in this virtual micrograph. It is made up of several fascicles, two of which are larger than the others. Within one of the larger fascicles, note the wide range in axon diameter. The axon appears as a dot in the middle of a clear space, which is the region occupied by lipid-rich myelin (extracted during tissue preparation). Most peripheral nerves carry both afferent (sensory) and efferent (motor) fibers. (adapted from U of Mich histology)Other similar posts