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Theodor Schwann one of the "fathers of cytology." The letter S


A name perhaps unknown to many but well known to those involved in biology and in particular of the nervous system. Two hundred years ago
December 7, 1810 was born in Germany, then Prussia, Theodor Schwann was one of the world's top scientists whose discoveries have made do with biology and medicine in particular the enormous advances in the understanding of human physiology. Schwann is considered, along with Schleiden, a founder of modern cell theory. In 1836 he was the first to assert that the phenomenon of fermentation was due to the action of microorganisms, Schwann was opposed and ridiculed by Liebig in particular the theory of which was in opposition with that proposed by Schleiden and Schwann. Following the doggedness of his colleagues, Schwann was forced to emigrate from Germany, which denied it access to all University and took refuge in Belgium. His work is the generalization of the principle of modern histology, pathology, and later led to rely on real science.
Within each of us are important cells in the peripheral nervous system without which we would be suffering from serious diseases such cells are named for their discoverer, and in fact are called Schwann cells. These cells are responsible for enhancing the speed of conduction of nerve impulses along axons of cells nervose. Le cellule di Schwann si avvolgono numerose volte i attorno agli assoni dei neuroni come fossero dei manicotti e poiché contengono la mielina producono la nota guaina mielinica che conferisce la colorazione biancastra ai neuroni che riveste. Lo strato di mielina non forma un manicotto continuo, ma si organizza in tanti manicotti separati da interruzioni dette nodi di Ranvier. Questo fatto si verifica anche perchè le dimensioni delle cellule di Schwann sono molto minori di quelle degli assoni delle cellule nervose, alcuni dei quali raggiungono il metro di lunghezza. Il segmento di fibra compreso fra due nodi di Ranvier successivi si dice internodo o segmento internodale, esso è occupato da una sola cellula di Schwann
La mielina si comporta come un nastro insulation that has clocked along the path of the pulse, this particular condition causes an intermittent pattern of nerve impulses particularly fast. The impulse conduction, in fact, instead of proceeding in a linear "jumps" from one node to another, resulting in less energy-consuming and much faster. Comparing the speed of nerve impulse conduction of nerve fibers with myelin such as myelin unmyelinated so you move from a top speed of 10 m per second fibers without myelin to 150 meters per second in the axons of myelinated type A fibers.
And it is to changes in myelin related diseases, which today are the focus of major efforts in research are a few examples: multiple sclerosis or leukodystrophy. In the first case we speak of demyelinating disease in which myelin is gradually destroyed so that the nerve impulse is slowed in the second one speaks of congenital diseases, and genetic, and relate these dismielinizzanti alteration of metabolism or the synthesis of myelin.
In recent years, are making impressive progress in research in particular through the use of stem cells in the expectation that these reached the damaged parts, will turn into myelin-producing cells or lining cells.