Lymphoid organs
Organa lymphoidea
- Latin synonym: Systema lymphoideum
- Synonym: Lymphoid system; Lymphatic organs
- Related terms: Lymphoid system
Definition
Lymphoid organs are specialized structures within the immune system that are involved in the production, maturation, and activation of lymphocytes. They are classified into three main categories:
1. Primary lymphoid organs: These include the thymus and bone marrow, where T and B lymphocytes, respectively, develop and mature independently of antigens.
2. Secondary lymphoid organs: These include lymph nodes, spleen, Peyer's patches, and mucosal-associated lymphoid tissues such as pharyngeal lymphoid ring (the tonsils) and adenoids. SLOs are sites where lymphocytes encounter antigens, leading to their activation and proliferation.
3. Tertiary lymphoid organs (TLOs): These are ectopic lymphoid structures that form in response to chronic inflammation and resemble SLOs in their cellular composition and organization.
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