Final answer:
The spleen and the tonsils are part of the lymphatic system, which plays a key role in the body's immune response and fluid balance. The lymphatic system is distinct from the digestive and circulatory systems, although it does interact with these systems.
Step-by-step explanation:
The organ system that includes the spleen and the tonsils is the lymphatic system. The lymphatic system is a critical part of the adaptive immune system, which is responsible for protecting the body against pathogens and maintaining fluid balance. It works closely with the cardiovascular system by transporting lymph, a fluid containing infection-fighting white blood cells, throughout the body. The lymphatic system has various components, including lymph organs like the spleen and tonsils, lymph vessels, lymph nodes, and lymph (fluid).
The tonsils are located in the throat region and consist of three pairs: the palatine tonsils at the back of the mouth, the pharyngeal tonsils in the nasal cavity, and the lingual tonsils under the tongue. On the other hand, the spleen is the largest of the secondary lymphoid organs, positioned centrally in the body, and it serves the dual purpose of filtering blood and housing lymphocytes. It also acts as a site for breaking down aged red blood cells and is involved in immune surveillance.
While the lymphatic system is associated with the digestive and cardiovascular systems due to its fluid transport functions, it is distinct from these systems and serves unique roles in immune defense and lymph transport. Therefore, when discussing the spleen and tonsils specifically, the correct reference is the lymphatic system and not the digestive or circulatory systems.