The cortex and medulla of an adult thymus (40X)

Histologically, the adult thymus still maintains a distinct division into the outer cortical region and the inner medullary region, though the cortex appears less densely packed with thymocytes compared to that in children. The cortical area in the adult thymus may show more scattered, smaller clusters of immature thymocytes. The medulla, which houses mature T-cells, remains relatively unchanged in appearance, containing characteristic Hassall's corpuscles and specialized epithelial cells that contribute to the development of regulatory T-cells.