Final answer:
Lymphoid nodules are clusters of lymphocytes and other cells found in the lymph nodes and tonsils. They are located in the respiratory and digestive tracts and do not have a surrounding fibrous capsule like the spleen and lymph nodes.
Step-by-step explanation:
The clusters of lymphocytes and other cells that are constant features in the lymph nodes and tonsils are called lymphoid nodules. Lymphoid nodules are clusters of lymphocytes and other cells found in the lymph nodes and tonsils. They are located in the respiratory and digestive tracts and do not have a surrounding fibrous capsule like the spleen and lymph nodes.
These nodules are located in the respiratory and digestive tracts, areas routinely exposed to environmental pathogens. Unlike the spleen and lymph nodes, lymphoid nodules do not have a surrounding fibrous capsule and consist of a dense cluster of lymphocytes.