Schwann cells are glial cells that were originally discovered by Theodore Schwann, a co-founder of the cell theory, during the nineteenth century. These cells are now known to be involved in maintaining the peripheral nervous system (PNS) and can be subdivided into two types, myelinated and non-myelinated. These cells wrap around the axons of the PNS, and due to the nature of their plasticity, they are able to perform a variety of essential functions. Function The key function of Schwann cells is the myelination, or simply the insulation of axons. This fatty covering aids in the conduction of neuronal signals, allowing for efficient transmission. These cells also aid in the elimination of cellular debris, regeneration and upkeep of axons. Additionally, Schwann cells are actively involved in creating an inflammation reaction as a response to an injury of the PNS. Because injuries can lead to damaged axons, Schwann cells aid in fixing axonal damage and promoting new growth. Due to their healing properties, these cells can be used in spinal cord injuries to encourage regeneration of damaged axons. Finally, these multipurpose cells are key in the formation of protective outer barrier, or the perineurial sheath, that creates a vital separation for peripheral nerves. Associated conditions There are also several diseases linked to Schwann cells that ought to be noted. To begin with, some demylelinating disorders include: multiple sclerosis, Charcot-Marie-Tooth disease (CMT), and Guillain–Barré syndrome. Although science has yet to offer up conclusive evidence that Schwann cell transplantation is an effective treatment for demylelinating disorders, it is possible that this could be applied in clinical practice in the future. There are also two inherited tumor disorders that have been connected with Schwann cells, neurofibromatosis type 1 and type 2. While both are genetic conditions associated with benign tumors, neurofibromatosis type I are neurofibromas and are therefore composed of a variety of cells and elements including Schwann cells and mast cells among others. In contrast, neurofibromatosis type II is characterized by schwannomas located on the eighth cranial nerve. This unfortunate placement leads to disruptions in balance, hearing and sometimes even vision. Description While schwannomas in a general sense can be found in a variety of places where Schwann cells are located,<unk> s are a rare but serious condition that specifically targets the eye. These tumors are thought to come from Schwann cells of the ciliary nerves and have also been called "pseudomelanomas" and for good reason. They are given this name due to the fact that they often resemble a common and dangerous eye tumor, a uveal malignant melanoma. This commonality can lead to misdiagnosis and the unnecessary enucleation of an eye as a result. Because of this confusion, schwannomas are most often diagnosed after removal. While it may be difficult if not impossible to make the distinction on the basis of routine examination and diagnostic measures, it is key to be aware of the possibility of<unk> s and look for any atypical features that may present themselves.
Intraocular schwannoma
Optic nerve sheath meningioma
Optic nerve glioma
Optic nerve tumor
Intraocular lymphoma
Vestibular schwannoma
Orbital lymphoma
Coloboma of optic nerve