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• What is the main function of the lymphatic system?

  Return lymph from tissues to bloodstream

  
• How does the lymphatic system relate to the circulatory system?

  It complements the functions of the bloodstream

  
• What does the lymphatic system regulate in the body?

  Balance of fluids
• What does the lymphatic system filter from the blood?

  Pathogens
• What begins the lymphatic system?

  Lymphatic capillary meshwork

  
• What does lymph travel through to reach the bloodstream?

  Larger lymph vessels

  
• What do lymphoid organs contain that monitors incoming lymph?

  Immune cells
• What is lymph?

  Clear, yellowish fluid in tissues

  
• How is lymph created?

  Filtration of plasma through capillary walls
• What percentage of interstitial fluid becomes lymph?

  About 10%

  
• What varies in lymph composition?

  Location of lymph production
• What are lacteals?

  Special lymphatic capillaries absorbing nutrients
• What are lymphatic capillaries?

  Smallest lymphatic vessels collecting interstitial fluid

  
• How are lymphatic vessels categorized?

  Superficial and deep lymphatic vessels
• Where are superficial lymphatic vessels located?

  In the subcutaneous layer of the skin
• What do deep lymphatic vessels carry lymph from?

  Internal organs
• What assists lymph flow in deep lymphatic vessels?

  Pulsation of arteries and skeletal muscle contractions
• What are the four pairs of lymphatic trunks?

  Lumbar, bronchomediastinal, subclavian, jugular
• What is the function of valves in lymphatic vessels?

  Promote unidirectional flow of lymph
• What do afferent lymphatic vessels do?

  Bring lymph to the lymph node
• What happens when foreign particles are detected in lymph?

  Immune response is initiated
• What are lymphocytes?

  Main immune cells in the body
• Where do lymphocytes arise from?

  Stem cells in primary lymphoid organs
• What are the three major groups of lymphocytes?

  B lymphocytes, T lymphocytes, NK cells

  
• What do B lymphocytes do?

  Produce antibodies to destroy antigens
• What is the role of T lymphocytes and NK cells?

  Directly kill infected or cancerous cells
• What are the primary lymphoid organs?

  Bone marrow and thymus

  
• What happens to T cells after they arise from stem cells?

  They travel to the thymus for differentiation

  
• What is antigen-dependent activation?

  Final maturation process of lymphocytes
• What is bone marrow responsible for?

  Production of blood cells
• What are the two types of bone marrow?

  Red marrow and yellow marrow
• Where is red marrow most abundant?

  In all skeletal structures until age 5
• What supports the cells in bone marrow?

  Reticulin, a type III collagen
• What is the thymus?

  Encapsulated primary lymphoid organ
• What is hematopoiesis?

  Process of blood cell production
• What are the regions of the thymus?

  Subcapsular cortical, cortical, medullary

  
• What characterizes the cortex of the thymus?

  Darker region with more T-lymphocytes

  
• What are thymic epithelial cells?

  Endodermal derivatives that differentiate in thymus
• What do cytoreticular cells do in the thymus?

  Present antigens and release cytokines
• What forms the corticomedullary barrier?

  Inner layer of squamous cortical thymic epithelial cells