Lymphatic Vessels

Lymphatic vessels perform several critical functions for immune and circulatory health:

• Fluid Balance: Return excess interstitial fluid to the bloodstream to prevent edema
• Immune Transport: Carry lymphocytes and antigen-presenting cells to lymph nodes for immune activation
• Waste Removal: Transport cellular waste and pathogens for clearance
• Nutrient Absorption: Absorb dietary fats and fat-soluble vitamins from the digestive system via lacteals
• Integration with Blood Circulation: Maintain blood volume and support cardiovascular function

Key Takeaway

Lymphatic vessels are essential conduits for immune cells, nutrients, and waste products, ensuring fluid balance, immune defense, and efficient nutrient transport throughout the body.

Basic Structure

• Composed of thin endothelial-lined vessels with one-way valves
• Begin as lymphatic capillaries in tissues and merge into larger vessels
• Contain smooth muscle layers in larger vessels to help propel lymph

Major Regions

• Lymphatic Capillaries: Tiny, blind-ended vessels in almost all tissues
• Lymphatic Collecting Vessels: Merge capillaries and transport lymph toward lymph nodes
• Lymphatic Trunks: Drain large regions of the body
• Thoracic Duct & Right Lymphatic Duct: Return lymph to venous circulation at the subclavian veins

Nerves & Blood Supply

• Passive flow relies on skeletal muscle contraction, respiration, and valves
• Autonomic nerves regulate smooth muscle contraction in larger vessels

Key Takeaway

Lymphatic vessels’ valve-equipped, hierarchical structure allows them to efficiently collect interstitial fluid, transport immune cells, and maintain fluid and immune system homeostasis.

• The lymphatic system carries approximately 2–4 liters of lymph per day
• Lymphatic vessels are crucial for immune surveillance and early pathogen detection
• Lymphatic valves prevent backflow, ensuring one-way transport
• Lacteals in the small intestine absorb dietary fats and fat-soluble vitamins
• Unlike blood, lymph does not have a central pump; movement relies on muscle activity and pressure changes

• Lymphedema: Swelling due to blocked or damaged lymphatic vessels
• Lymphangitis: Infection or inflammation of lymphatic vessels
• Lymphatic Obstruction: Can occur due to tumors, surgery, or trauma
• Immune Deficiencies: Impaired lymph transport affects immune function
• Chylothorax: Accumulation of lymphatic fluid in the thoracic cavity

• Swelling or puffiness in limbs (especially arms or legs)
• Slow wound healing or frequent infections
• Fatigue or poor detoxification
• Recurrent inflammation or fluid retention
• Digestive issues due to impaired fat absorption

Source: CrashCourse