False-colour scanning electron micrograph of the subcapsular sinus of a lymph node showing a number of lymphocytes (white blood cells, the spherical yellow objects). Lymph nodes are encapsulated, kidney-shaped structures mostly located at intervals along lymph vessels. Functions include filtration of lymph by scavenging macrophages and production & storage of both B & T lymphocytes. A labyrinth of cells and cell processes in the various sinuses serves to slow the flow of fluid through the node facilitating the actions of lymphatic cells involved in the immune response processes. Magnification: x780 at 6x7cm size.