LYMPHOID TISSUES 04

This field shows a lymph nodule in the palatine tonsil, although there is no information in the field that would allow one to identify this as having come from a tonsil (much less as having come specifically from the palatine). Most of the field is occupied by the germinal center of the nodule, with a small portion of the denser perimeter of the nodule being visible to the right. Germinal centers arise when lymphocytes, responding to antigenic "challenge", begin to divide, and differentiate, and (often) die. Such regions contain lymphoblasts and lymphocytes in all stages of the cell cycle and various functional states. There are also numerous macrophages (phagocytic cells that take up the debris from dying cells); because these have a larger ratio of cytoplasm:nucleus than do most lymphocytes, the macrophages tend to appear as relatively pale spots scattered throughout the germinal center. The arrow labeled "M" points to a cell undergoing mitosis, while the letters "P" are placed near the nuclei of macrophages.

Slide L-3, field S9/S10 of finder slide A, 16X objective