text: <unk>  (also<unk>  and sheath of Schwann) is the outermost layer of nerve fibers in the peripheral nervous system. It is a nucleated cytoplasmic layer of Schwann cells that surrounds the myelin sheath of axons.
  Unlike the axon and the myelin sheath, the<unk>  does not degenerate after a nerve has been cut or crushed; the hollow tube formed by the<unk>  is instrumental in regenerating the nerve fiber. It is important to note that in CNS, axons are myelinated by oligodendrocytes, thus lack<unk> .
option_0: Neurolemma
option_1: Somatrem
option_2: Amnion
option_3: Ethoprophos
option_4: Libido
option_5: Triclofos
option_6: Heroic
option_7: Cholinergic