In vertebrates, the axons of many neurons are sheathed in myelin, which is formed by either of two types of glial cells: Schwann cells ensheathing peripheral neurons and oligodendrocytes insulating those of the central nervous system.

The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.

Neurons, Schwann cells, and fibroblasts work together to create a working nerve.

Schwann cells and neurons exchange molecular signals that regulate survival and differentiation.

Demyelinating Schwann cells causes abnormal axon structure and function.

The sheaths are formed by glial cells: oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system.

Neurons are sometimes called nerve cells, though this term is potentially misleading since many neurons do not form nerves, and nerves also include non-neuronal Schwann cells that coat the axons in myelin.

A very important type of glial cell ( oligodendrocytes in the central nervous system, and Schwann cells in the peripheral nervous system ) generates layers of a fatty substance called myelin that wraps around axons and provides electrical insulation which allows them to transmit action potentials much more rapidly and efficiently.

In recent research done in mice, it was found that the cleavage of PrP proteins in peripheral nerves causes the activation of myelin repair in Schwann Cells and that the lack of PrP proteins caused demyelination in those cells.

The disorder affects all neural crest cells ( Schwann cells, melanocytes and endoneurial fibroblasts ).

* 1839 — Theodor Schwann proposed that all animal tissues are composed of cells.

Schwann and Schleinden argued that cells are the elementary particles of life.

The Cell Theory states that all organisms are composed of cells ( Schleiden and Schwann ), and cells can only come from other cells ( Virchow ).

Another cell involved in CMT is the Schwann cell, which creates the myelin sheath, by wrapping its plasma membrane around the axon in a structure that is sometimes compared to a Swiss roll.

As a consequence, the fibres are covered with myelin produced by oligodendrocytes, rather than Schwann cells, which are found in the peripheral nervous system, and are encased within the meninges.

Myelinating Schwann cells wrap around axons of motor and sensory neurons to form the myelin sheath.

In myelinated axons, Schwann cells form the myelin sheath ( see above ).

Myelinating Schwann cells begin to form the myelin sheath in mammals during fetal development and work by spiraling around the axon, sometimes with as many as 100 revolutions.

A well-developed Schwann cell is shaped like a rolled-up sheet of paper, with layers of myelin in between each coil.

Outside the myelin sheath is a cellular layer called the neurilemma or sheath of Schwann cells.

Schwann cells form myelin in the peripheral nervous system ( PNS ).

Schwann cells can also make a thin covering for an axon which does not consist of myelin ( in the PNS ).

A peripheral nerve fiber consists of an axon, myelin sheath, Schwann cells and its endoneurium.

In 1838, Theodor Schwann began studying white and grey matter in the brain, and discovered the myelin sheath.

A single oligodendrocyte can extend its processes to 50 axons, wrapping approximately 1 μm of myelin sheath around each axon ; Schwann cells, on the other hand, can wrap around only 1 axon.

* Myelinopathy, or " demyelinating polyneuropathy ", is due to a loss of myelin ( or of the Schwann cells that make and contain it ).

This discovery later led Ranvier to careful histological examination of myelin sheaths and Schwann cells.

In the internodal region, the Schwann cell has an outer collar of cytoplasm, a compact myelin sheath, and inner collar of cytoplasm, and the axolemma.

At the junction of two Schwann cells along an axon, the directions of the directions of the lamellar overhang of the myelin endings are of opposite sense.

The term " vestibular schwannoma " involves the vestibular portion of the 8th cranial nerve and arises from Schwann cells, which are responsible for the myelin sheath in the peripheral nervous system.

The crucial difference is that in the CNS, including in the spinal cord, myelin sheaths are produced by oligodendrocytes and not by Schwann cells.

PNS is much faster and efficient at clearing myelin debris in comparison to CNS, and Schwann cells are the primary cause of this difference.

Schwann cells continue to clear up the myelin debris by degrading their

** The Wallace Lab and Muir Lab at the University of Florida in Gainesville, Florida focus on the molecular study of benign Schwann cell tumors and the development of new therapies for NF1.

Credit for developing cell theory is usually given to three scientists: Theodor Schwann, Matthias Jakob Schleiden, and Rudolf Virchow.

Schwann cells are involved in many important aspects of peripheral nerve biology — the conduction of nervous impulses along axons, nerve development and regeneration, trophic support for neurons, production of the nerve extracellular matrix, modulation of neuromuscular synaptic activity, and presentation of antigens to T-lymphocytes.

Non-myelinating Schwann cells are involved in maintenance of axons and are crucial for neuronal survival.

In the past two decades, many studies have demonstrated positive results and potential for Schwann cell transplantation as a therapy for spinal cord injury, both in aiding regrowth and myelination of damaged CNS axons.

Indeed, Schwann cells are known for their roles in supporting nerve regeneration.

Schwann cells are essential for the maintenance of healthy axons.

Non-myelinating Schwann cells such as those that form Remak bundles and terminal Schwann cells are positive for S-100 and Glial fibrillary acidic protein ( GFAP ).

The recent identification of the Schwann cell microvilli protein gliomedin as the likely binding partner of axonal neurofascin brings forward substantial evidence for the importance of this protein in recruiting Nav channels to the nodes of Ranvier.

However, the macrophages are not attracted to the region for the first few days ; hence the Schwann cells take the major role in myelin cleaning until then.

An energy deficiency in Schwann cells would account for the disappearance of myelin on peripheral nerves, which may result in damage to axons or loss of nerve function altogether.

The movement of the axons ( and subsequently the Schwann cells ) is guided by the growth cone, a filamentous projection of the axon that actively searches for neurotrophins released by the myotube.

Sometimes they are found on glia, such as Schwann cells, radial glia and Bergmann glia cells and, as such, are important for neural cell migration during development.

In a paper published in the January 2010 issue of Science, an international team of researchers announced that devil facial tumour disease likely originated in Schwann cells, a type of cell found in the peripheral nervous system that is essential for the functions of nerve cells in the peripheral nervous system.

It is an autocrine growth factor as well as a mitogen for astrocytes, Schwann cells, and fibroblasts.