CHAPTER 16: LYMPHATIC SYSTEM AND IMMUNITY OBJECTIVES 1. Name the organs that compose the lymphatic system and give three general functions performed by this system. Bone Marrow Control Disease Thymus Lymph nodes Spleen Transport dietary fat Transport excess tissue fluid back to blood stream 2. Trace the flow of lymph from interstitial tissues to the bloodstream. 1
3. Discuss the function of anchoring filaments that surround lymphatic capillaries. Open the space between lymphatic capillary cells so leaked tissue fluid can enter. 4. Name four tissues that do not contain lymphatic capillaries. CNS Splenic pulp Bone marrow Avascular tissues 5. Give the special name for lymphatic capillaries within the wall of the small intestine. Lacteals 6. Distinguish between an afferent and efferent lymphatic vessel. Afferent Efferent Toward (Lymph Node) Exit (Lymph Node) 7. Explain how lymphatic vessels are similar to veins. They carry low pressure fluid against gravity. They are equipped with valves. Lymph movement is aided by skeletal muscle actions and breathing action. 8. List the six primary body regions drained by lymphatic trunks. Jugular trunk Bronchomediastinal trunk Intercostal trunk Subclavian trunk Intestinal trunk Lumbar trunk 2
9. Name the two lymphatic collecting ducts and indicate the portion of the body that is drained by each. Right Lymphatic Duct Thoracic Duct (Left Lymphatic Duct) Drains Left and lower right (75%) of body Drains upper right 25% of body 10. Name the vein that each of the two collecting ducts deposit their lymph. Subclavian vein 11. Discuss the composition of interstitial fluid and lymph. Plasma components minus proteins 12. List the functions of lymph, noting its major function. Absorb and transport dietary fats Collects excess interstitial fluids and deliver back to the bloodstream Deliver foreign particles to lymph nodes for removal and destruction (phagocytosis by macrophages). 3
13. Explain the forces involved in the movement of lymph. It is similar to venous blood movement. It is aided by the action of skeletal muscle, respiratory movement and valves in lymphatic vessels. 14. Name the condition that occurs when lymphatic flow is obstructed. Edema_ 15. Discuss the structure, location, and major function of lymph nodes. Structure: Bean shaped. Located along lymphatic pathways. Convex side receives the afferent lymphatic vessels. The efferent vessel leaves on the concave side. Location: Cervical, Axillary, Supratrochlear, Thoracic, Abdominal, Pelvic, Inguinal Functions: Filter and remove debris from lymph for removal and destruction (phagocytosis by macrophages). 4
16. Discuss the structure, location, and major function of the spleen. Located behind the stomach on the left side and it filters debris and worn cells from blood. White pulp = lymphocytes Red pulp = red blood cells, lymphocytes and macrophages. 17. Distinguish between the body fluids filtered by lymph nodes and those filtered by the spleen. Lymph nodes filter lymph Spleen filters blood 18. Name the cell responsible for the filtering action of the lymph node and spleen. Macrophage 19. Discuss the structure, location, and major function of the thymus. Located within the mediastinum, soft bi-lobed and decreases in size in adults. The function is to process T-cells in immunity. 5
20. Name the hormone secreted by the thymus that causes maturation of lymphocytes that have migrated to other tissues. Thymosin 21. Describe what happens to the thymus as one ages. Shrinks 22. Define the term pathogen. Disease causing agent. Bacteria, viruses, protozoa, etc. 23. Label the diagram below re: Lines of Defense Against Infection. 6
24. Define the term non-specific (innate) resistance and discuss the body's seven major mechanisms. Non specific (innate) general defenses, protects against many pathogens. Mechanical Barriers: Skin & Mucous Membranes Chemical Barriers: Enzymes, Acid, Salt, interferons, defensins, collectins, complement) Phagocytosis Inflammatory response Fever Species resistance 25. Name the antibacterial enzyme present in tears. Lysozyme 26. Discuss how interferons, defensins, and collectins aid in fighting infection. Interferon Secreted by non-infected cells in response to the presence of viruses. They interfere with proliferation of viruses. Defensins destroys bacteria by punching holes in cell walls Collectins Protect by attaching themselves to a variety of microbes. Provide broad protection against them. 27. List the cardinal signs of inflammation. Redness = rubor Swelling = tumor Heat = calor Pain = dolor 7
28. List the steps involved in the inflammatory process. Inflammation is a tissue response to damage, injury, or infection. Blood Vessels dilate increasing capillary permeability so blood floods area. Chemicals released by damaged tissues attract various white blood cells to the site of injury. Tissue fluid leaks into area Fibroblasts arrive 29. Discuss the importance of phagocytosis, and indicate the origin of phagocytic cells. Phagocytosis special white blood cells that destroy foreign particles from tissues and body fluids. Origin Neutrophils or monocytes in the blood are called phagocytes. Those that leave the blood through diapedesis are called macrophages. 30. Define the term adaptive resistance/ immunity. Specific attack on an antigen. 31. Define the term antigen, and discuss how antigens cause immune responses to occur. Substance (usually a protein) that causes the formation of an antibody & reacts specifically with that antibody causing an immune response. 8
32. Discuss the origin and maturation of lymphocytes. Stem cells in red bone marrow give rise to undifferentiated lymphocytes that are released into the blood. Those that reach the thymus are processed into T-Cells; those that are not processed by the thymus are most-likely processed in the fetal bone marrow and are called B-Cells. The T & B cells are transported through the bloodstream and also inhabit lymphatic organs. 33. Discuss the process by which an immune response occurs, beginning with the antigen-presenting cell. Macrophages in the tissues receive the antigen first. They present the antigen to the T- cell, which then activates the B-Cell. 9
34. Distinguish between T cells and B cells. T-Cells B-Cells processed in the thymus Function in cell mediated immunity processed in fetal bone marrow Function in antibody-mediated immunity. 35. Distinguish between Cell-Mediated Immunity (CMI) and Antibody-Mediated (or humoral) Immunity (AMI). Cell Mediated Immunity/ Cellular Immune Response Provided by T-cells processed in the thymus Provide a direct attack with antigen or antigenbearing agent to destroy them Antibody Mediated Immunity Humoral Immune Response Provided by B-cells Processed in fetal bone Marrow Provide indirect attack by producing antibodies that bind with antigen or antigen-bearing agent to destroy them 36. Discuss the general structure of an antibody (immunoglobulin [Ig]). Resemble a Y, with 4 amino acid chains; 2 heavy chains, and 2 light chains. 10
37. Name the five major classes of immunoglobulin s and list the major characteristics of each. IgG 80% Most abundant. Only antibody to cross placenta. IgA 13% Defends against bacteria and viruses. Tears, saliva, breast milk. IgM 6% 1 st antibody to be secreted after initial exposure. Located in plasma. IgD <1% Located on the surface of most B lymphocytes. IgE <.1% Involved in allergic response. Located on exposure gland secretion. 38. Name the most abundant Ig. IgG 39. Name the only Ig that can cross the placenta. IgG 40. Name the Ig produced during a primary immune response (IR). IgM 41. Name the Ig produced in abnormal amounts during allergic reactions. IgE 42. Discuss the many actions of antibodies. Attack antigens directly Direct Attachment involves agglutination, precipitation, neutralization. Activation of complement (Positive feedback mechanism) Opsonization, chemotaxis, inflammation, lysis. 43. Distinguish between agglutination, precipitation, neutralization, and lysis. Agglutination: Antigens clump Precipitation : Antigens become insoluble Neutralization : Antigens lose toxic properties Lysis : Cell membrane ruptures 11
44. Name the positive feedback mechanism that is activated by antibodies and list its effects. Complement 45. Compare and contrast a primary IR vs. a secondary IR. IgM (Primary) IgG(Secondary) Slow Huge/Quick 46. Discuss the four practical classifications of immunity. Naturally Acquired (ACTIVE) Live Pathogen Suffer disease symptoms Artificially Acquired Vaccine containing dead or weakened (ACTIVE) pathogen Possible mild symptoms or no disease symptoms Naturally Acquired IgG Antibodies that cross placenta from (PASSIVE) Artificial Acquired (PASSIVE) mom to fetus Injection of gamma globulin with ready made antibodies. No immune response, short term immunity. 47. Explain how immediate-type allergic reactions occur and proceed. Inherited Causes production of high IgE ;levels When allergens combine with IgE, this causes mast cells to burst and release histamine causing tissue damage. Symptoms: hives, hay fever, asthma, eczema, gastric disturbances, anaphylactic shock. 12
48. Name the four types of transplants performed. Isograft Autograft Allograft Xenograft 49. Discuss the major problem that occurs in autoimmune disorders, and list some possible causes of autoimmunity. Can t distinguish self from non-self. Maybe caused by previous viral infection, faulty T-Cell development, persistent fetal cells. 50. Explain the theory of microchimerism, as it relates to autoimmunity (AI). Microchimerism seen Scleroderma most likely due to persistent fetal cells. This may explain predominance of AI in females. 13