Final answer:
The spleen is an important secondary lymphoid organ involved in the adaptive immune response by filtering blood, capturing pathogens, and activating lymphocytes. The bone marrow and thymus gland are primary lymphoid organs where B cells and T cells mature, respectively. Secondary organs like tonsils and lymph nodes also play significant roles.
Step-by-step explanation:
An important lymphoid organ and immunologic effector tissue is the spleen. The spleen functions as a secondary lymphoid organ that filters pathogens from the blood and removes degenerating or damaged blood cells. It plays a crucial role in the adaptive immune response by capturing pathogens and antigens that pass into it, making it a site where pathogens encounter and activate lymphocytes. The activated lymphocytes then mount an adaptive immune response, which is instrumental in the body's defense against infections.
Other important lymphoid organs include the bone marrow, which is a primary lymphoid organ where B cells mature, and the thymus gland, where T cells mature. Secondary lymphoid organs such as tonsils and lymph nodes also contribute to the functioning of the immune system by filtering lymph and storing lymphocytes, which are activated upon encountering pathogens.