rhythmic contraction of smooth muscle in larger lymph vessel walls Some connecting directly to lymph nodes Lymph and Lymph Vessels: Lymphatic Vessels, Trunks, and Ducts Lymphatic Trunks Fed into by lymphatic vessels On both right and left side of body Jugular trunks drain lymph from head and neck Subclavian trunks drain upper limbs, breasts, and superficial thoracic wall Bronchomediastinal trunks drain deep thoracic structures Intestinal trunks drain most abdominal structures Lumbar trunks drain lower limbs, abdominopelvic wall, and pelvic organs Largest lymphatic vessels Drained into by lymphatic trunks Two lymphatic ducts: right lymphatic duct and thoracic duct Convey lymph back into venous circulation Right lymphatic duct located near right clavicle receives lymph from: right side of head and neck right upper limb right side of thorax returns lymph at junction of right subclavian and right internal jugular veins Thoracic duct larger of two ducts from diaphragm to junction of left subclavian and left jugular veins drains lymph from remaining body left side of head and neck left upper limb left side of thorax abdomen and both lower limbs has saclike structure at base, cisterna chyli named for lipid-rich lymph, chyle, from vessels draining GI tract left and right intestinal and lumbar trunks draining here travels superiorly from cisterna chyli lies directly anterior to vertebral bodies passes through aortic opening of the diaphragm ascends to left of vertebral body midline Clinical View: Lymphedema Accumulation of interstitial fluid Occurs 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 resulting in scar e.g., surgery requiring removal of lymph nodes Can be controlled with compression garments, exercise, and massage Overview of Lymphatic Tissue and Organs Primary lymphatic structures Involved in formation and maturation of lymphocytes Red bone marrow and thymus Secondary lymphatic structures Not involved in lymphocyte formation House lymphocytes and other immune cells Provide site of immune response initiation Include lymph nodes, spleen, tonsils, and lymphatic nodules Include MALT (mucosa-associated lymphatic tissue) Primary Lymphatic Structures: Red bone marrow Located within spaces between trabeculae in sections of spongy bone in flat bones of skull, vertebrae, ribs, and sternum ossa coxae, proximal epiphyses of humerus and femur Responsible for hemopoiesis produces erythrocytes, platelets granulocytes, and agranulocytes T-lymphocytes and B-lymphocytes two major types of lymphocytes T-lymphocytes migrating to thymus to complete maturation Primary Lymphatic Structures: Thymus Thymus Bilobed organ in superior mediastinum Functions in T-lymphocyte maturation Quite large in infants and young children grows until puberty begins to regress and much replaced by adipose tissue Consists of two fused thymic lobes each surrounded by connective tissue capsule
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- Spring '10
- lymph node, lymphatic capillaries