It is compromised of [[Primary Lymphoid Tissue - Anatomy & Physiology|primary]] and [[Secondary Lymphoid Tissue - Anatomy & Physiology|secondary]] lymphoid systems that are composed of lymphoid tissues that both mature and proliferate lymphocytes. | It is compromised of [[Primary Lymphoid Tissue - Anatomy & Physiology|primary]] and [[Secondary Lymphoid Tissue - Anatomy & Physiology|secondary]] lymphoid systems that are composed of lymphoid tissues that both mature and proliferate lymphocytes. |