What organ system includes the lymphatic system?

The lymphatic system is critically involved in the immune system as it plays a key role in defending the body against pathogens. It is responsible for transporting lymph, a fluid that contains infection-fighting white blood cells, throughout the body. This system includes structures such as lymph nodes, the spleen, and the thymus, which are vital for maintaining immune function.

Additionally, the lymphatic system helps to return excess interstitial fluid to the bloodstream, thus contributing not just to fluid balance but also to the removal of waste products and toxins from tissues. By facilitating the movement and maturation of lymphocytes and other immune cells, the lymphatic system directly supports the overall function of the immune system, making this connection fundamental in understanding how the body's defenses operate.