* Lymphatic ducts are fed by lymphatic trunks * Largest lymphatic vessels * Bring lymph to venous blood circulation * There are two: right lymphatic duct and thoracic duct * Right lymphatic duct is near right clavicle * Drains upper right quadrant of body * Right side of head and neck, right upper limb, and right side of thorax * Delivers lymph to junction of right subclavian and right internal jugular veins * Thoracic duct is largest lymphatic vessel * Runs from diaphragm to junction of left subclavian and left jugular veins * Saclike cisterna chyli at its base * Receives lipid-rich chyle from GI tract * Drains lymph from left side of head and neck, left upper limb, left side of thorax, abdomen, and both lower limbs
Lymphedema * Accumulation of interstitial fluid due to interference with lymphatic drainage * Causes swelling and pain in affected area * May interfere with wound healing and contribute to infection * Most caused by blockage of lymph vessels * E.g., trauma or infection of lymph vessels or tumors * E.g., radiation therapy scarring or surgical removal of lymph nodes * Controlled with compression garments, exercise, massage * Extreme cases known as elephantiasis * Caused by infection with parasitic worms
verview of Lymphatic Tissue and Organs * Primary lymphatic structures * Involved in formation and maturation of lymphocytes * Red bone marrow and thymus * Secondary lymphatic structures * Do not form lymphocytes, but house them and other immune cells * Sites of immune response initiation * Include lymph nodes, spleen, tonsils, and lymphatic nodules * Include MALT (mucosa-associated lymphatic tissue)
Primary Structures: Red Bone Marrow * Red bone marrow * Located between trabeculae of spongy bone * In flat bones of skull, ribs, and sternum, vertebrae, ossa coxae, heads of humerus and femur * Site of hemopoiesis : production of blood’s formed elements * Formed elements include T - lymphocytes and B - lymphocytes * T-lymphocytes migrate to thymus to complete maturation
Primary Structures: Thymus * The thymus is involved in T-lymphocyte maturation * Located in mediastinum * Larger in children than adults * Grows until puberty, then regresses; gradually replaced by adipose tissue * Consists of two thymic lobes, each surrounded by connective tissue capsule * Trabeculae of capsules subdivide lobes into lobules * Each lobule has outer cortex and inner medulla regions * Both regions are lymphoepithelial (contain lymphatic cells and epithelial tissue) * Cortex contains immature T-lymphocytes * Medulla contains mature T-lymphocytes
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- Fall '08
- right lymphatic duct, lymph node, *right lymphatic duct