Lymphatic System

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Lymphatic System
2013-11-12 20:37:53

Lymphatic System
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  1. Functions of Lymphatic System
    • Returns excess interstitial fluid to blood (including plasma or proteins) 
    • Transports dietary lipids from digestive system to blood
    • Carries out immune responses
  2. Lymph
    • Liquid mixture of fluid and solutes
    • Includes most components of blood plasma 
    • More fluid filters out of blood capillaries than is reabsorbed 
    • Returned to bloodstream via lymph vessels
  3. Lymphatic Capillaries
    • Beginning of lymphatic network 
    • Closed-ended tubes located near most blood capillaries
    • Endothelial Cells overlap
    • Structure allows interstitial fluid to flow in but NOT out
    • Merge to form lymph vessels 
    • Lacteals - Lymph capillaries in small intestines
  4. Lacteals
    • Lymph capillaries in small intestine (carry chyle)
    • Special lymphatic capillary in small intestine
    • Chyle - Milky color; carry dietary fats 
  5. Lymphatic Vessels
    • Form from lymphatic capillaries 
    • Contain valves that prevent backflow 
    • Resemble veins (thinner walls & more valves)
    • Where lymph nodes are found (Alters lymph)
    • Follow same route as veins in hypodermis & arteries in viscera
  6. Lymphatic Trunks
    • Form from merging lymphatic vessels (after vessels exits lymph nodes)
    • Trunk drain major body region into one of two ducts
  7. Principal Trunks
    • Lumbar trunk
    • Intestinal trunk
    • Bronchomediastinal trunk
    • Subclavian trunk
    • Jugular trunk
  8. Lumbar Trunk
    Drain lower limbs, abdominopelvic wall, and pelvic organs
  9. Intestinal Trunk
    Drain most abdominal structures
  10. Bronchomediastinal Trunk
    Drain deep thoracic structures
  11. Subclavian Trunk
    Drain lymph from upper limbs, breasts, and superficial thoracic wall
  12. Jugular Trunk
    Drain lymp from head and neck
  13. Lymphatic ducts
    • Drained into by lymphatic trunks
    • Empty lymph back into the venous circulation
  14. Right Lymphatic Duct
    • Located near R clavicle
    • Receives from R. jugular, R. subclavian & R. bronchomediastinal trunks
    • Returns/Drains lymph into the junction of R subclavian and R internal jugular veins
  15. Thoracic Duct
    • Largest lymph vessel
    • Begins as cisterna chyli (dilated sack) 
    • Receives from all L. trunks & lower R. Trunks
    • Main duct for return of lymph to blood
    • Returns/Drains into junction of L. Internal Jugular & L. Subclavian veins
  16. Primary lymphatic Organs
    • Site of stem cell division & immunocompetence 
    • Cells develop ability to mount immune response
    • Red Bone Marrow
    • Thymus
  17. Red Bone Marrow Gives rise to
    • Mature B cells
    • Immature T cells 
    • (lymphocytes)
  18. Thymus gives rise to
    Mature T cells
  19. Thymus Location
    Mediastinum, between sternum & aorta
  20. Thymus
    • Populates second lymphatic organ & tissue with T-cells 
    • Consists of two thymic lobes
    • Two lobes divided by C.T. trabeculae into lobules
    • Each lobules contains Outer cortex and Deeper medulla
  21. Seconday Lymphatic Organs
    Site where most immune responses occur

    • Lymph nodes 
    • Spleen
    • Lymphatic Nodules (MALT & Tonsils)
  22. Lymph Nodes
    • Where lymph is altered/cleaned
    • Often located along lymph vessels in clusters from receiving regions
    • Site of proliferation of B cells & T cells
  23. Spleen
    • Largest mass of lymphatic tissue
    • Filters blood
    • Macrophages destroy pathogens and remove worn RBCs & platelets 
    • B cells & T cells perform immune functions
  24. Afferent lymphatic vessels
    Carry lymph to the Lymph Node
  25. Efferent Lymph Vessels
    Carry Lymph away from Lymph Node
  26. Lymphatic Nodules
    • Tissue, not organ
    • Scattered through mucosa (M.A.L.T.)
    • Tonsils
  27. Tonsils
    • Located around pharynx 
    • Protects again inhaled/ingested foreign substances
  28. M.A.L.T.
    • Mucosa-Associated lymphatic tissue
    • Located in the mucosa of the gastrointestinal, respiratory, genital, and urinary tracts
    • Detects antigens and initiate immune response
  29. Crypts
    • Invaginated outer edges of tonsils 
    • Help trap material and facilitate its ID by lymphocytes
  30. Lymphatic/Lymphoid Cells
    • In lymphatic & cardiovascular systems 
    • Work together to elicit an immune response 
    • -Macrophages & Dendrite cells 
    • -Epithelial cells 
    • Lymphocytes (B cells, T cells, NK cells)
  31. Macrophages & Dendritic cells
    • Derived from monocytes 
    • Help alert other lymphatic cells to foreign molecules
  32. Epithelial Cells
    Secret thymic hormones to assist in maturation of T cells
  33. Macrophages
    • Monocytes that have migrated into the lymphatic system from bloodstream
    • Responsible for phagocytosis of foreign substances 
    • May also present antigens to other lymphatic cells
  34. Dendritic cells
    • Found in the lymphatic nodules 
    • Main antigen-presenting cell
    • Internalize antigens from lymph and present them to other lymphatic cells
  35. T Cells
    • T-lymphocytes that mature in the Thymus 
    • 70-80% of body lymphocytes 
    • Better at protecting again viral, fungal, cancer  infections
    • Recognize particular antigen
    • (lymphocyte) 
  36. B Cells
    • B-lymphocytes matured in Bone Marrow
    • 15-30% of lymphocytes in body
    • Contain receptors to respond to certain antigen and stimulate the production of immunoglobins(anti-bodies)
    • Divide into Plasma cells and Memory B cells
    • (Lymphocyte) 
  37. Natural Killer Cells (NK cells)
    • Attack any body cell with abnormal or unusual plasma membrane proteins.
    • Unlike T or B cells which respond to a specific antigen
  38. Plasma Cells
    • Rise from B cells 
    • Produce antibodies
    • Custom made for certain molecules
    • (lymphocytes) 
  39. Memory B Cells
    • Rise from B cells 
    • Provide long-term immunity
    • Longer life span than plasma cells 
    • (Lymphocyte)
  40. Helper T cells
    • Secrete multiple regulatory substances 
    • affects activity of other T cells & B cells 
    • Type of T Cell
  41. Cytotoxic T Cells
    • Directly destroys microbes
    • Type of T Cell
  42. Memory T Cell
    • Recognize foreign antigen after initial exposure
    • Mount a faster immune response to repeated exposures
  43. Supressor/Regulatory T cell
    • Inhibits B cell activity 
    • Appear to "turn off" immune response once its been activated
  44. Vaccines
    • Deliberately introduce milder or dead form of antigen to immune system 
    • Makes immune responses quicker & more intense after subsequent exposure 
    • Inhibits Memory cells