Schwann cells are histologically part of the nervous tissue, because they are closely related to what are neurons, these cells cover the prolonged portion of neurons called axons, where they run synapses with other neurons, being Surrounding the neuronal axon, the Schwann cells form a protein sheath known as myelin, without this the transmission of the nerve impulse is impossible. This type of cells are found from the birth of the neuron to its full development, playing an important role in maturation Likewise, for the Schwann cells to myelinize (make the myelin sheath) the neuron, its axon must have a considerable diameter.
Some neurons do not have these mentioned cells, this is because the developed axon does not have an appreciable diameter, as well as they may be present but do not completely envelop the axon, making myelination impossible; As mentioned, the sheath results from the spiral union of numerous layers of Schwann cells, along the axon between one Schwann cell and another, unmyelinated spaces remain, these intercellular spaces They are given the name of the nodes of Ranvier, these points are important when transmitting the nerve impulse, because they accelerate the path of the action potential in the cell without having to enlarge the diameter of the axon, giving an effect of "Saltatorial conduction" since it is a movement that looks like a jump between node and node.
Another function of this type of tissue is to provide support and slow but progressive repair of neurons that suffer some injury. Normally the diseases that generate demyelination of the neuron, is because they cause a destruction of the Schwann cells, among which can be mentioned is multiple sclerosis, or an autoimmune disease, progressively generating a limitation for muscle contraction, decreasing thus the power of bodily movement in man. The origin of the cells is embryonic, and they were discovered by the hand of the German scientist Teodor Shcwann, between the years 1810 and 1822.
