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Lymphatic System Gross Anatomy. ANHB 2212 - 2006 Avinash Bharadwaj. Blood, Tissue Fluid and Lymph. Blood capillaries “Extravasation” of fluid Tissue fluid and exchange. Not all the fluid returns to blood vessels. Lymph flows through lymphatic vessels before returning to larger veins.
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Lymphatic SystemGross Anatomy ANHB 2212 - 2006 Avinash Bharadwaj
Blood, Tissue Fluid and Lymph • Blood capillaries • “Extravasation” of fluid • Tissue fluid and exchange • Not all the fluid returns to blood vessels. • Lymph flows through lymphatic vessels before returning to larger veins. • Lymph may contain micro-organisms and other “unwanted” material • Needs to be “filtered” • Lymph nodes : More than physical filters
Lymph Nodes • Histological structure and function : Friday! • Small structures – few mm in size • Scattered all over the body • Regional groups and “drainage territories” • Variable number and pattern • Broad principles
Lymphatic Drainage – Concepts – 1 • Importance • Infections • Infectious agents carried by lymph • Immune responses in lymph nodes • Enlargement of lymph nodes • Malignancies (cancers) • Cancerous cells break loose from the main mass • Carried by lymph • Trapped in lymph nodes further growth • Enlargement of nodes (destruction of normal structure) • Diseases of lymph nodes • Some specific infections
Lymphatic Drainage – Concepts – 2 • Lymphatic vessels form plexuses • Series of lymph nodes • Usually two to four sets before bloodstream • Many routes of drainage • Blockage may lead to opening of alternative routes • Different descriptions and terminology
Regional Nodes – Limbs • Upper limb • First nodes around the elbow (few) • Major sets in the axilla • Also drain abdominal and thoracic walls including the breast • Lower limb • First nodes behind the knee • Major sets in the groin (inguinal region) • Also drain abdominal wall, lower back, perineum
Regional Nodes – Head and Neck • Superficial and deep • General direction of flow : superficial deep • Superficial nodes in the superficial fascia • Deep nodes mainly around carotid sheath
Regional Nodes – Thorax • Thoracic wall – Axillary! • Thoracic viscera • Nodes around trachea and bronchi • Tracheobronchial • Bronchopulmonary • Also : paratracheal, paraoesophageal
Regional Nodes – Abdominal Wall • Axillary and Inguinal • Boundary (“Watershed”) through the umbilicus • No lymph nodes in the wall itself
Regional Nodes : Abdominal Viscera • Multiple sets especially for the GI Tract • Final set around the aorta • Developmental correlation • GIT Tract – unpaired midline structures • Nodes in front of the aorta : preaortic • Other organs – paired, lateral • Kidneys, suprarenals, gonads • Nodes lateral to aorta : para-aortic
Digestive System Organs • Nodes close to the wall of the organ • Nodes along the arteries • Preaortic nodes • Illustrated by the colon here.
Pre- Lateral Lymphangiography Abdominal Nodes at a Glance • Para-aortic (also called lateral aortic) • Upper : paired glands (note : these include the gonads!) • Also drain lymphatics along lumbar arteries • Lower nodes : drain inguinal nodes • Pre-aortic – grouped around the origins of the three arteries. • All abdominal nodes cisterna chyli thoracic duct Last Slide