<Tr> <Th> MeSH </Th> <Td> D012583 </Td> </Tr> <Tr> <Td_colspan="2"> Anatomical terms of neuroanatomy (edit on Wikidata) </Td> </Tr> <P> Schwann cells (named after physiologist Theodor Schwann) or neurolemmocytes are the principal glia of the peripheral nervous system (PNS). Glial cells function to support neurons and in the PNS, also include satellite cells, olfactory ensheathing cells, enteric glia and glia that reside at sensory nerve endings, such as the Pacinian corpuscle . The two types of Schwann cells are myelinating and nonmyelinating . Myelinating Schwann cells wrap around axons of motor and sensory neurons to form the myelin sheath . The Schwann cell promoter is present in the downstream region of the human dystrophin gene that gives shortened transcript that are again synthesized in a tissue - specific manner . </P> <P> During the development of the PNS, the regulatory mechanisms of myelination are controlled by feedforward interaction of specific genes, influencing transcriptional cascades and shaping the morphology of the myelinated nerve fibers . </P>

What cells form the myelin sheath around nerve fibers in the pns