Which organ, essential for maturation of T lymphocytes, has a cortex and medulla?

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!

T cells mature in the thymus, an organ that uniquely shows a cortex and a medulla. In the dense cortex, developing thymocytes interact with cortical thymic epithelial cells, where positive selection ensures they can recognize self-MHC molecules. As they mature, they move to the medulla, where negative selection weeds out self-reactive cells with the help of medullary thymic epithelial cells and Hassall’s corpuscles. This cortex–medulla organization is a hallmark of the thymus and underpins T cell maturation. The other organs—lymph nodes, spleen, and appendix—do not provide this thymic maturation environment, even though they participate in immune responses or contain lymphoid tissue.