Which organ filters blood and contains white pulp and red pulp?

Study for the CAMLPR Histology Practice Test. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

The spleen is the organ that filters blood and contains both white pulp and red pulp. The white pulp is immune tissue organized around central arteries (the periarterial lymphoid sheaths, or PALS) and includes B-cell follicles, forming the site where blood-borne antigens are detected by lymphocytes. The red pulp consists of splenic cords and sinusoids, where aging or damaged red blood cells are removed by macrophages and where blood cells can be stored. This combination distinguishes the spleen from other organs: the liver also filters blood but lacks the distinct white/red pulp architecture; lymph nodes filter lymph rather than blood and have cortex and paracortex rather than white and red pulp; and the thymus is a primary lymphoid organ for T cell development with cortex/medulla, not white/red pulp.