(from the Greek for “multi-branched cells”), also known as oligodendroglia, are a type of neuroglia whose main function is to provide a myelin sheath for neuronal axons in the central nervous system (CNS). Myelination provides metabolic support and isolates the axons of most vertebrates. A single oligodendrocyte can elongate its processes, covering up to 40 axons, including several adjacent axons. The myelin sheath is segmented along the length of the axon by intervals known as Ranvier intercepts. Oligodendrocytes are found both in gray matter (where they represent most of the perineuronal elements) and in white matter (where they are responsible for the formation of myelin, these oligodendrocytes have long processes). One of the types of oligodendroglia is Schwann cells. These cells are located in the peripheral nervous system, are able to spirally wrap their cytoplasm around the axons of neurons and form myelin sheaths. Those oligodendrocytes that are located in the gray matter of the central nervous system are located so tightly to the bodies of neurons that they are called satellite cells. The main functions of oligodendrocytes are: isolation – Schwann cells completely restrict all neuronal parts of the peripheral nervous system from connective tissue; synthetic – Schwann cells take on the task of creating the myelin protein and ensuring its structural and functional integrity. Myelination in embryonic ontogenesis occurs quite late and takes weeks and months after birth. The main function is that myelin allows you to increase the speed of nerve impulse conduction.