In another example of the cortex of a lymph node (HA17), note the density of the small lymphocytes. Both cortical and medullary areas are packed with cells. In the lymph nodule (HA17, n) in this image, there is a rim or “cap” of very densely packed lymphocytes surrounding lighter, germinal center. This is known as a secondary follicle. The numbers of primary (no germinal center) and secondary follicles vary widely from node to node, and are directly related to the degree of antigenic stimulation. Surrounding the nodules are quite large areas of dense lymphatic tissue, extending into the medulla as medullary cords (right, HA17).