What is the role of lymph nodes in the lymphatic system?

Lymph nodes play a crucial role in the lymphatic system, primarily functioning to filter lymph and activate immune responses. They are small, bean-shaped structures distributed throughout the body, acting as key sites for the monitoring and filtration of lymph fluid, which contains substances such as bacteria, viruses, and other foreign particles.

When lymph fluid, which is collected from tissues throughout the body, passes through lymph nodes, immune cells like lymphocytes and macrophages can detect any pathogens present. If foreign invaders are recognized, these immune cells are activated, leading to a coordinated immune response. This response includes the proliferation of lymphocytes and the production of antibodies, which help to neutralize or eliminate pathogens.

The other options do not accurately describe the primary functions of lymph nodes. While blood filtration is a function of the kidneys and spleen, lymph nodes specifically deal with lymphatic fluid. Storing hormones is not a function associated with lymph nodes; instead, glands like the thyroid or adrenal glands fulfill that role. Additionally, red blood cell production occurs in the bone marrow, not in lymph nodes, which are more involved in immune regulation and response.