Lymph Node

LYMPH NODE

Lymph nodes are small, bean-shaped structures, measuring 1–25 mm in length. They are found in the neck, armpits, groin, and other regions.

Each lymph node is covered by a dense connective tissue capsule. Lymph nodes often swell during infections, indicating immune activity.

Structure of Lymph Node

• Outer capsule of fibrous tissue
• Internal stroma divided into cortex and medulla
• Trabeculae extend inward
• Cortex contains lymph follicles
• Germinal centers are sites of B-cell proliferation
• Medulla contains plasma cells and macrophages
• Hilum allows entry and exit of vessels

Afferent vessels bring lymph into the node, and efferent vessels carry filtered lymph away.

Functions of Lymph Node

• Filters lymph and removes pathogens
• Exposes antigens to immune cells
• Activates B-cells and T-cells
• Produces lymphocytes
• Removes dead cells and cancer cells
• Produces plasma proteins like globulins