Lymphatics

• What is lymph?


  Fluid lost from the capillary bed that collects in the tissues
• How does lymph collect in the body?

  Lymph collects in the tissues after fluid is lost from the capillary bed
• What structures drain lymph into the lymphatic system?

  Lymphatic vessels
• What is the appearance of clear lymph?

  Clear in color
• What is milky lymph from the small intestine called?

  Chyle
• How does lymph move around the body?

  Small lymphatic vessels join to form larger vessels that pass through nodes
• What do lymph nodes contain?

  Lymphocytes and macrophages
• In which direction does lymph move in the body?

  From the periphery towards the midline and eventually the upper thorax
• What are the primary and secondary lymphoid organs?

  • Primary lymphoid organs:
  • Bone marrow
  • Thymus
  • Secondary lymphoid organs:
  • Spleen
  • Tonsils
  • Lymph nodes
  • Peyer’s patches
  • GALT (Gut Associated Lymphoid Tissue)
  • BALT (Bronchiolar Associated Lymphoid Tissue)
  • MALT (Mucosa Associated Lymphoid Tissue)
• What happens to T lymphocytes in the thymus?

  T lymphocytes become immunologically competent
• Where do B cells become immunologically competent?

  In the bone marrow
• How do T and B cells interact with lymphoid tissues?

  • T and B cells seed other lymphoid tissues
  • Mature cells circulate among lymphoid tissues
• Why is lymph important for the body?

  It collects interstitial fluid, proteins, and cells and returns them to the bloodstream
• What role do lymph nodes play in the immune system?

  Lymph nodes help to remove damaged cells and pathogens
• What does lymph node swelling indicate?

  It indicates a problem, possibly infection or disease
• How can slow lymph flow through a node affect health?

  It may lead to cancer cells forming secondary tumors within nodes
• How can lymph be visualized?

  By using dye to follow lymphatic pathways
• What happens to lymph nodes when they are infected?

  Lymph nodes become enlarged
• What is a lymphogram?

  A procedure to visualize the lymphatic system
• What is the appearance of lymph fluid?

  Clear or milky
• Why are tiny lymphatic vessels not seen in direct radiography (DR)?

  Because they are too small to be visualized
• How does the structure of lymphatic vessels compare to veins?

  Lymphatic vessels are similar in structure to very small veins
• Lymphatic vessels are thin-walled, one cell thick, with no smooth muscle or elastic tissue.
• Lymphatic vessels are one-way valves that prevent backflow.
• What are the main lymphatic ducts in the body?

  Lumbar trunks, cisterna chyli, thoracic duct, and right lymphatic duct
• What does the right jugular trunk drain?

  The right side of the head and neck
• What does the right subclavian trunk drain?

  The right upper limb and the superficial structures of the upper part of the thorax and abdominal walls on the right side
• What does the right bronchomediastinal trunk drain?

  The deep thoracic structures on the right side
• What structures are equivalent to the right lymphatic duct on the left side of the body?

  Left jugular, left subclavian, left bronchomediastinal trunks, and the thoracic duct
• What is the function of the thoracic duct?

  It collects lymph from various trunks and the thoracic wall
• Where does the thoracic duct empty?

  Into the junction of the left subclavian and left jugular veins
• What are the main groups of lymph nodes in the body?

  • Each region of the body has its own small local groups of lymph nodes
  • Lymph drains from these nodes to larger, more central groups of nodes
  • Important to be aware of small groups for practical examinations

  
• Which lymph nodes are specified for examination in practical classes?

  Superficial inguinal, axillary, or tracheobronchial nodes
• What are the lymph nodes associated with the thorax?

  • Nodes at the bifurcation of the trachea and lung hilum
  • Axillary nodes
  • Parasternal nodes
• What are the lymph nodes associated with the abdomen?

  • Pre-aortic and para-aortic nodes
  • Coeliac (foregut)
  • Superior mesenteric (midgut)
  • Inferior mesenteric (hindgut)
• What are the lymph nodes associated with the pelvis?

  • Superficial and deep inguinal nodes
  • Common, external, and internal iliac nodes
  • Testis and ovaries to para-aortic nodes
• What are the lymph nodes associated with the lower limb?

  • Popliteal nodes
  • Femoral nodes
  • Inguinal nodes (deep and superficial)
  • To iliac nodes
• What are the lymph nodes associated with the head and neck?

  • Parotid, sublingual, submental, and auricular nodes
  • Jugular and cervical nodes
  • No nodes for the brain