Peripheral Nerve Domain

The peripheral nerve domain is a region in the PNS in which peripheral neurons becomes surrounded by Schwann cells. Schwann cell generation begins with differentiation of neural crest cells into Schwann precursor cells, which then mature to form immature Schwann cells. At birth, the immature cells differentiate into either the myelinating or nonmyelinating Schwann cells, through a process called radial sorting, which then populate the mature nerves. The myelinating Schwann cells envelop axons of peripheral motor and sensory neurons with diameters exceeding 1µm in diameter, while unmyelinating Schwann cells envelop axons of peripheral neurons with diameters smaller than 1µm. An unmyelinating Schwann cell envelops multiple small axons, called a Remak bundle and do not and produce myelin.