Thymus Cortex

The thymic cortex is heavily filled with developing T-lymphocytes. At the outer cortex, it is common to find mitotic figures. These are dividing lymphoblasts in the process of producing clones of smaller mature T-cells. The epithelial cells in the cortex express class I and class II MHC and serve to positively select immature T-cells. At the corticomedullary junction, one can find pale-stained macrophages. These macrophages remove lymphocytes that have undergone apoptosis because they failed to develop properly.