Why are the thymus and the spleen considered organs of the lymphatic system?

The thymus and spleen are considered organs of the lymphatic system because they play crucial roles in the immune response and lymphocyte maturation. The thymus is responsible for the development and maturation of T lymphocytes (T cells), which are essential for adaptive immunity. The spleen filters blood, removing old or damaged red blood cells, and also serves as a site for the activation of B lymphocytes (B cells) and T cells, thereby facilitating immune responses. Together, they help maintain the body's defense mechanisms against pathogens and manage lymphatic circulation.