Lymphatic System Organs: Functions and Locations

The lymphatic system comprises primary and secondary lymphoid organs that coordinate immune responses and fluid balance.

Primary Lymphoid Organs

• Bone Marrow: Site of hematopoiesis and B-cell maturation.
• Thymus: T-cell maturation and selection (located in mediastinum).

Secondary Lymphoid Organs

• Lymph Nodes: Bean-shaped filters along lymphatic vessels; contain B and T cells; site of antigen presentation.
• Spleen: Filters blood; removes old RBCs; mounts immune response to blood-borne pathogens (left upper quadrant).
• MALT (Mucosa-Associated Lymphoid Tissue): Includes tonsils, Peyer's patches (ileum), appendix; protects mucosal surfaces.

Lymphatic Vessels

Thin-walled capillaries and larger vessels transport lymph (interstitial fluid + immune cells) back to venous circulation via the thoracic duct and right lymphatic duct.