Lymph Node Histology: Video, Causes, & Meaning

Introduction to the Lymphatic System

• Essential part of the immune system
• Composed of lymphatic vessels, tissues, and organs
• Functions to drain interstitial fluid (lymph) from tissues back to the blood

Lymphoid Organs

• Primary Lymphoid Organs:
  • Thymus
  • Bone marrow
• Secondary Lymphoid Organs:
  • Tonsils
  • Lymph nodes
  • Spleen
  • Mucosa-associated Lymphoid Tissue (MALT)

Structure and Function of Lymph Nodes

• Small, bean-shaped secondary lymphoid organs
• Located along lymphatic vessels throughout the body
• Size: Approximately 1 cm in short axis and 2.5 cm in long axis
• Play a role in the immune system by filtering lymph to identify and combat infections

Detailed Anatomy of Lymph Nodes

• Outer Capsule:
  • Composed of connective tissue
• Functional Regions:
  • Outer Cortex:
    • Contains B-cell follicles with germinal centers
    • Germinal centers are sites where B cells differentiate into plasma cells
  • Inner Cortex (Paracortex):
    • Lacks nodules
  • Medulla:
    • Contains cords of lymphoid tissue and medullary sinuses
    • Sinuses facilitate lymph drainage into efferent lymphatic vessels

Importance of Lymph Nodes

• Critical for the body's immune response
• Contain clusters of lymphocytes and other white blood cells to fight infections

Summary

• Lymph nodes are essential for the immune system, aiding in infection control
• Found throughout the body, particularly in the neck, groin, and underarms
• Comprised of key structural components crucial for their function

Additional Resources and Information

• Content Reviewers: Rishi Desai, MD, MPH
• Contributors: Justin Ling, MD, MS, Kaylee Neff, Evan Debevec-McKenney

For additional learning and resources, refer to the provided links and further reading on the Osmosis website.