Schwann cells are the neuroglia that produces myelin sheaths. There is a formation of multiple layers of the glial plasma membrane around axons. The cytoplasm and nucleus of Schwann cells from the outermost layer while the inner part has multiple layers of the Schwann cell membrane. The outer nucleated cytoplasmic layer of the Schwann cell that encloses the myelin sheath is called neurolemma. It is found only around axons in the PNS. Its function is to serve in the regeneration of injured axons by the formation of a regeneration tube.
Wallace is often referred to as the father of modern biogeography. 6. The finger bones inside manatee and whale flippers are evidence that these living species are modified forms of older species.
