What is the primary function of the lymph nodes?

The primary function of the lymph nodes is to filter lymph and trap pathogens. Lymph nodes act as a crucial component of the immune system. They are strategically located throughout the body and serve as checkpoints where lymphatic fluid, which contains lymphocytes (a type of white blood cell), is filtered. This filtration process allows the lymph nodes to identify and respond to pathogens such as bacteria and viruses that may be present in the lymph fluid. When pathogens are detected, the lymph nodes can initiate an immune response, activating the lymphocytes to help fight off infections and protect the body. This function is essential for maintaining overall health and immune defense.

The other options pertain to different functions that are not directly related to the primary role of lymph nodes. Hormone production, fat storage, and blood circulation involve other organs and systems within the body, such as the endocrine system, adipose tissues, and the cardiovascular system, respectively.