Schwann Cell Lineage.
Schwann cell generation starts with differentiation of neural crest into Schwann precursor cells, followed by their maturation into immature Schwann cells. Schwann cells progressively sort axons from the main bundle; the Schwann cells which associate with a single large-diameter axonal segment become myelinating Schwann cells. In contrast, immature Schwann associated with several small caliber axons become non-myelinating Schwann cells.
Each myelinating Schwann cell forms a myelin sheath around the axon, known as a node of Ranvier. This structure allows the action potential to jump from one node of Ranvier to another. The non-myelinating Schwann cells are important for providing support and nutrition to the axon, ensuring their survival.