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).
See the diagrams above. Figures (1), (2) and (3). Neurilemma. The sheath of the axon of a nerve fibre. The neurilemma of a medullated fibre contains myelin laid down by Schwann cells. Neurone. A cell specialized to transmit electrical nerve impulses and so carry information from one part of the body to another. Neurone = Nerve Cell