Page 434 - Atlas of Histology with Functional Correlations
P. 434
FIGURE 11.1 ■ Location and distribution of the lymphoid organs and
lymphatic channels in the body.
IMMUNE SYSTEM ORGANS: LYMPH
NODES, SPLEEN, AND THYMUS
The lymph nodes are widely distributed and are primarily found along the paths
of lymphatic vessels that are prominent in inguinal and axillary regions. A
connective tissue capsule surrounds the lymph node and sends its trabeculae
into its interior. The lymph node exhibits an outer cortex and an inner medulla.
A network of reticular fibers and spherical, nonencapsulated aggregations of
lymphocytes called lymphoid nodules characterize the cortex, some of which
exhibit lighter-staining central areas called germinal centers. The medulla
consists of medullary cords and medullary sinuses. Medullary cords are
networks of reticular fibers filled with plasma cells, macrophages, and
lymphocytes separated by capillary-like channels called medullary sinuses (Fig.
11.2).
433
