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

Lymph nodes play a critical role in the immune system primarily by activating immune cells and trapping germs. As part of the lymphatic system, these small, bean-shaped structures are strategically located throughout the body. They serve as sites where lymph, a fluid containing infection-fighting white blood cells, is filtered.

When pathogens, such as bacteria and viruses, enter the body, they are carried by the lymphatic fluid to the lymph nodes. Here, immune cells, including lymphocytes (B cells and T cells), are activated in response to the detected pathogens. The nodes provide an environment where these immune cells can proliferate and mount an effective immune response. This process ensures that potential threats are identified and neutralized, playing a vital role in protecting the body from disease.

The other options do not accurately reflect the primary functions of lymph nodes. They do not produce hormones, filter blood, or store energy, which are all roles played by other systems or organs in the body.