What is the role of the spleen in the immune system?

The spleen plays a crucial role in the immune system primarily through its function in the filtration of blood and the activation of immune responses. As blood circulates through the spleen, it is filtered to remove old or damaged red blood cells, pathogens, and debris. This filtering process is essential for maintaining healthy blood composition and ensuring that potential threats to the body are effectively dealt with.

In addition to filtration, the spleen houses various immune cells, including lymphocytes and macrophages, which are vital for orchestrating immune responses. When pathogens are detected in the blood, these immune cells become activated, leading to the production of antibodies and the initiation of responses that target and eliminate the pathogens. The spleen thus acts as a hub for immune cell interaction and activation, making it an integral component of the body's defense mechanism against infections.

The other choices do not accurately describe the principal functions of the spleen. While hormones may be produced in various organs, the spleen is not primarily known for this function. Similarly, although some fat is stored in the body, fat storage is not a specialized function of the spleen. Finally, the production of red blood cells occurs mainly in the bone marrow, not in the spleen, making this option incorrect in the