Lymph Nodes: Your Body's Pathogen Filtration System

Lymph nodes are encapsulated lymphoid organs strategically placed along lymphatic vessels. They filter lymph and initiate adaptive immune responses.

Key Cellular Components

• Macrophages: Phagocytose pathogens, debris, and apoptotic cells; present antigens to T cells.
• Lymphocytes:
  • B cells: In follicles/germinal centers; differentiate into plasma cells producing antibodies.
  • T cells: In paracortex; CD4+ helpers, CD8+ cytotoxic, regulatory T cells.
• Dendritic Cells: Professional antigen-presenting cells migrating from tissues.
• Reticular Cells (Fibroblastic Reticular Cells): Form a stromal network (reticulum) supporting cellular traffic and conduit system for lymph flow.

Function

Lymph enters via afferent vessels, percolates through the cortex and medulla, where antigens are trapped and presented. Activated lymphocytes proliferate, differentiate, and exit via efferent vessels to target infection sites.