Page 443 - Atlas of Histology with Functional Correlations

lymphatic nodules (13) situated adjacent to each other but separated by

internodular connective tissue trabeculae (5, 14) and trabecular (cortical)
sinuses (6). In this illustration, two lymphatic nodules (13) are illustrated. Some
lymphatic nodules exhibit a central, light-staining germinal center (7, 15)
surrounded by a denser-staining peripheral portion (13). In the germinal centers
(7, 15), the cells are loosely aggregated with the developing lymphocytes

showing larger and lighter-staining nuclei with more cytoplasm.

The deeper portion of the lymph node cortex is the paracortex (8, 17), a
thymus-dependent zone primarily occupied by T cells. This area represents the
transition from the lymphatic nodules (7, 13) to the medullary cords (9, 19) of

the lymph node medulla. The medulla consists of anastomosing cords of
lymphatic tissue, the medullary cords (9, 19), interspersed with medullary
sinuses (10, 18) that drain the lymph from the node into the efferent lymphatic
vessels in the hilus (see Fig. 11.2).

Fine reticular connective tissue provides support for the lymph node and

forms the core of the lymphatic nodules (13) in the cortex, the medullary cords
(9, 19), and all medullary sinuses (10, 18) in the medulla. Because few
lymphocytes are seen in the medullary sinuses (10, 18), it is possible to

distinguish the reticular framework in the lymphatic nodules (13) and the
medullary cords (9, 19). The lymphocytes are so abundant that the fine reticulum
is obscured, unless specifically stained, as shown in Figure 11.9. Most of the
lymphocytes are small with large, deep-staining nuclei with condensed
chromatin and either a small amount of cytoplasm or none at all.

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