Photomicrograph of an infant human thymus. This H&E preparation reveals multiple lobules separated by connective tissue trabeculae that extend into the organ from the surrounding capsule. Each lobule is composed of a dark-staining basophilic cortex and a lighter-staining and relatively eosinophilic medulla. The medulla is actually a continuous branching mass surrounded by the cortex. The cortex contains numerous densely packed lymphocytes, whereas the medulla contains fewer lymphocytes. Note that in some instances the medulla may bear a resemblance to germinal centers of lymphatic nodules (upper right and center left). Such isolated medullary profiles are continuous with the overall medullary tissue, but this continuity may not be seen within the plane of section. x25.
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