1. lymphatic system consists of 3 parts:
    • 1. a network of lymphatic vessels (lymphatics)
    • 2. lymph - intersstitial fluid that has entered the lymphatic system
    • 3. lymph nodes- cleanse lymph & contain macrophages that destroy microorganisms & cell debris in lymph
  2. lymphatic system functions:
    • 1. returns interstitial fluid & plasma proteins back to blood that leaked from capillaries during blood/tissue exhange
    • 2. together w/lymphoid organs & tissues, provide the structural basis of immune system
    • 3. 1 way system, lymph flows toward heart
  3. lymph vessels include:
    • lymphatic capillaries - smallest
    • lymphatic collecting vessels
    • lymphatic trunks & ducts - largest
  4. once interstitial fluid enters lymphatics, its called:
  5. lymphatic capillaries are similiar to blood capillaries, except:
    • 1. very permeable
    • 2. endotheial cells overlap to form 1 way minivalves & are anchored by collagen filaments preventing collapse of capillaries
  6. when interstitial fluid is higher in capillaries than that of the lymphatic vessel:
    the flaps gap open allowing lymph to flow into the vessel
  7. when pressure is greater in the vessel:
    the valves close preventing lymph from returning to the interstitial fluid
  8. specialized lymph capillaries present in intestinal mucosa (lining of digestive tract)
  9. absorb digested fat and deliver fatty lymph(chyle) to the blood
  10. protects the digestive & respiratory systems from foreign matter:
    mucosa associated lymphatic tissue ( MALT)
  11. lymphatic collecting veins are similiar to veins except:
    • 1. have thinner walls w/more internal valaves
    • 2. collecting vessels in the skin travel w/superficial veins
    • 3. deep vessels travel w/arteries
    • 4. nutrients are supplied from branching vasa vasorum
  12. vessels of vessels; small vessels that supply large vessels w/blood
    vasa vasorum
  13. formed by the union of the largest collecting ducts:
    lymphatic trunks
  14. largest collecting ducts of the lymphatic trunk;
    • 1. paired lumbar: back
    • 2. paired bronchomediastinal - middle chest
    • 3. paired subclavian - under the clavicle
    • 4. paired jugular trunks - neck
    • 5. a single intestinal trunk - abdomen
  15. drains the right upper arm & the right side of the head & thorax
    right lymphatic duct
  16. arises from the cisternal chyli (collecting vessel) & drains the rest of the body
    thoracic duct
  17. condition where the lymphatic vessels become inflamed & the vasa vasorum become congested w/blood; visible at the surface of skin as red lines that are tender to touch
  18. lymph is propelled by:
    • 1. pulsations of nearby arteries
    • 2. contractions of smooth muscle in walls of the lymphatics
    • 3. pressure changes in the thorax while breathing
    • 4. no pump of its own - 1 way system
  19. swelling associated w/ tumors that block the lymphatic or removal of lymphatics during cancer surgery;
  20. very rare disorder characterized by non-cancerous growths (tumors) that may develop in the lymph node tissue at a single site or throughout the body;
    castlemans disease
  21. chemical messengers that communicate between immune cells:
  22. main warriors of the immune system
  23. 2 main varieties of lymphocytes:
    • T cells - killers
    • B cells - produce antibodies
  24. mature in thymus
    T cells (only 2% make it out of the thymus)
  25. mature in bone marrow
    B cells
  26. anything the body perceives as foreign, such as bacteria, viruses, cancer cells:
  27. manage the immune response; attack & destroy foreign cells
    T cells
  28. types of T cells:
    • helper T
    • cytotoxic T (cell destroying)
    • regulatory T (manage immune cells)
  29. produce plasma cells, which secrete antibodies to protect against future infections:
    B cells
  30. phagocytize foreign substances & help activate T cells (consume anything foreign):
  31. capture antigens & deliver them to lymph nodes:
    dendritic cells
  32. produce stroma (reticular fiber that supports other lymphoid cells) that support other cells in lymphoid organs - framework
    reticular cells
  33. two main types of lymphoid tissue:
    • diffuse lymphatic tissue
    • lymphatic follicles
  34. scattered reticular connective tissue elements found in every organ:
    diffuse lymphatic tissue
  35. solid, spherical bodies of tightly packed reticular elements & cells:
    lymphatic follicles (nodules)
  36. prinicpal lymphoid organs of the body; embedded in connective tissue in clusters along lymphatic vessels; only cluster near the body surface in groin, axillary & cervical regions:
    lymph nodes
  37. functions of lymph nodes:
    • 1. filter lymph-macrophages destroy microorganisms & debris
    • 2. immune system - lymphocytes encounter antigens, are activated & mount an attack against them
  38. circulation in the lymph nodes:
    • 1. lymph enters via afferent lymphatic vessels
    • 2. travels though large subcapsular sinus (where it's cleaned) & smaller sinuses
    • 3. exits the nodes at the hilus via efferent vessels
  39. largest lymphoid organ
  40. functions of the spleen:
    • 1. site of lymphocyte proliferation & immune surveillance & response
    • 2. cleanses the blood of aged cells & platelets and debris
    • 3. stores breakdown products for later reuse (ex: iron)
    • 4. stores blood platelets
    • 5. site of fetal erythocyte production (normally ceases after birth)
  41. mostly lymphocytes on reticular fibers (framework) & involved in immune functions:
    white pulp around central arteries (structure of the spleen)
  42. rich in macrophages for disposal of worn out RBC's & bloodborn pathogens:
    red pulp in venous sinuses & splenic cords (stucture of the spleen)
  43. it functions strictly in T lymphocyte maturation; doesn't directly fight antigens
  44. recognizes your cells vs. foreign cells (self vs. non self)
  45. simplest lymphoid organ; forms a ring of lymphatic tissue around pharynx:
  46. at posterior end of the oral cavity; most often infected
    palatine tonsils
  47. grouped at the base of the tongue
    lingual tonsils
  48. in posterior wall of the nasopharynx; called adenoids when enlarged
    pharyngeal tonsil
  49. surrounding the openings of the auditory tubes into the pharynx
    tubal tonsils
Card Set
lymphatic system