However, in scanning the entire tissue you should pick up areas where the medulla of one lobule is continuous centrally with that of another lobule. In fact, the medullary regions of the lobules are all continuous with one another. The cortex, at higher magnification, can be seen to be packed with lymphocytes . The majority of nuclei are those of lymphocytes. Epithelial reticular cells show very little cytoplasm.
Adjacent lymphocytes crowd right up to the nucleus.
On occasion you can see that reticular cells send off fine branches or partitions. Capillaries , but not venules can be seen in the cortex. The medulla is also rich in lymphocytes, but stains more lightly due to the decreased density of lymphocytes. Note that venules are present in the medulla. All of the blood vessels found in the thymic parenchyma are considered to be ensheathed by a layer of epithelial reticular cells, found outside the endothelial basal lamina.