GENERAL HISTOLOGY

Detailed explanation-1: -Depending on the location, different glial cell types make myelin in a different manner. 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).

Detailed explanation-2: -Myelin is present in the central nervous system (CNS) and peripheral nervous system (PNS); however only the central nervous system is affected by MS. CNS myelin is produced by special cells called oligodendrocytes.

Detailed explanation-3: -In the central nervous system (CNS), oligodendrocytes myelinate multiple axons; in the peripheral nervous system (PNS), Schwann cells (SCs) myelinate a single axon.

Detailed explanation-4: -The Schwann cell plays a vital role in maintaining the peripheral nervous system (PNS). Schwann cells are derived from neural crest cells, and come in two types either myelinating or non-myelinating Schwann cells. Both play a pivotal role in the maintenance and regeneration of axons of the neurons in the PNS.

Detailed explanation-5: -Myelinating Schwann cells are radially and longitudinally polarized cells (Salzer 2003; Ozcelik et al. 2010; Pereira et al. 2012). With myelination, Schwann cells organize into distinct membrane domains, each with a unique array of proteins, and a communicating set of cytoplasmic compartments (Fig.