For people with a psychotic illness, or who have a predisposition to such an illness, the effects can be more serious and long-term. Psychotic illnesses are characterised by symptoms such as delusions, hallucinations and thought disorder. When people experience psychotic symptoms, they are unable to distinguish what is real â there is a loss of contact with reality. See also Factsheet 1: Psychosis.
Structure [edit]. Schwann cells are a variety of glial cell that keep peripheral nerve fibres (both myelinated and unmyelinated) alive. In myelinated axons, Schwann cells form the myelin sheath (see above). The sheath is not continuous.Individual myelinating Schwann cells cover about 100 micrometres of an axonâequating to approximately 10,000 Schwann cells along a 1 metre length of the axon.n this sense, Schwann cells are the peripheral nervous system's analogues of the central nervous system 's oligodendrocytes. However, unlike oligodendrocytes, each myelinating Schwann cell provides insulation to only one axon (see image).
Confidence votes 48. Special glia called Schwann cells form the myelin sheath which cover axons in the peripheral nervous system. The myelin sheath is actually two layers. The first layer surrounding the axon is called the myelin sheath and it is made up of the plasma membrane of the Schwann cells. The Schwann cells cytoplasm creates the second layer and is called the neurolemma. A neuron in the peripheral nervous system with a myelin sheath is called a myelinated neuron.