Oligodendrocytes A Anatomy

Oligodendrocytes are the cells in the CNS that manufacture and maintain myelin, and as such they play an analogous role to the Schwann cells in the PNS. Hortega characterized oligodendrocytes in the 1920s using silver carbonate impregnation techniques. Not only did Hortega offer the first detailed morphological description of these cells, he also implied their role in myelination. Whereas oligodendrocytes are classified as a single cellular entity, they display a great degree of polymorphism. They are distributed throughout the entire CNS but are most prominent in white matter areas. They tend to be lineated in one of three ways: (1) aligned in rows along nerve fascicles, (2) juxtaposed against neuronal somata, and (3) abutting blood vessels. On the basis of these lineations, Hortega classified oligodendrocytes as interfascicular, perineuronal, and perivascular. In addition to categorizing oligodendrocytes on the basis of lineation, Hortega classified oligodendrocytes into four groups on the basis of morphology. Type 1 oligodendrocytes have spherical somata from which numerous processes project toward nerve fibers. Type 2 oligodendrocytes are located exclusively in white matter areas and have a cuboid cell body shape, with fewer and thicker processes associated with nerve fibers. Type 3 oligo-dendrocytes have only three or four processes emerging from the somata extending toward nerve fibers. Type 4 oligodendrocytes occur near the entrance of nerves into the CNS and adhere directly to nerve fibers. Improved staining technology using intracellularly injected dyes has increased morphological resolution and provides a more detailed picture of oligodendro-cytes. In addition to improved intracellular staining techniques, specific markers for oligodendrocytes have been developed, of which antimyelin basic protein is one of the most commonly used.

Breaking Bulimia

Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

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