HLT31507 CERTIFICATE III IN NUTRITION & DIETETIC ASSISTANCE

1. HLT31507 CERTIFICATE III IN NUTRITION & DIETETIC ASSISTANCE THE LYMPHATIC & IMMUNE SYSTEM delivered by: Mary-Louise Dieckmann

2. Consists of two semi-independent parts Lymphatic vessels Lymphoid tissues and organs Lymphatic system functions Transports escaped fluids back to the blood Plays essential roles in body defense and resistance to disease The Lymphatic System

3. Lymphatic collecting vessels Collect lymph from lymph capillaries Carry lymph to and away from lymph nodes Return fluid to circulatory veins near the heart Right lymphatic duct Thoracic duct Lymphatic Vessels

4. Entrance of right lymphatic duct into right subclavian vein Regional lymph nodes: Cervical nodes Internal jugular vein Thoracic duct entry into left subclavian vein Axillary nodes Thoracic duct Aorta Spleen Cisterna chyli (receives lymph drainage from digestive organs) Inguinal nodes Lymphatics KEY: Drained by the right lymphatic duct Drained by the thoracic duct Figure 12.3

5. Lymph—excess tissue fluid carried by lymphatic vessels Properties of lymphatic vessels One way system toward the heart No pump Lymph moves toward the heart Milking action of skeletal muscle Rhythmic contraction of smooth muscle in vessel walls Characteristics

6. Venous system Arterial system Heart Lymph duct Lymph trunk Lymph node Lymphatic system Lymphatic collecting vessels, with valves Lymph capillary Tissue fluid (becomes lymph) Blood capillaries Loose connective tissue around capillaries Figure 12.1

7. Lymph Vessels (Lymph Capillaries) Walls overlap to form flap-like mini valves Fluid leaks into lymph capillaries Capillaries are anchored to connective tissue by filaments Higher pressure on the inside closes mini valves Fluid is forced along the vessel Lymphatic Vessels

8. Tissue fluid Tissue cell Lymphatic capillary Blood capillaries Arteriole Venule (a) Figure 12.2a

9. Fibroblast in loose connective tissue Flaplike minivalve Filaments anchored to connective tissue Endothelial cell (b) Figure 12.2b

10. Harmful materials that enter lymph vessels includes: Bacteria Viruses Cancer cells Cell debris Lymph

11. Filter lymph before it is returned to the blood Defense cells within lymph nodes Macrophages—engulf and destroy foreign substances Lymphocytes—provide immune response to antigens Lymph Nodes

12. Entrance of right lymphatic duct into right subclavian vein Regional lymph nodes: Cervical nodes Internal jugular vein Thoracic duct entry into left subclavian vein Axillary nodes Thoracic duct Aorta Spleen Cisterna chyli (receives lymph drainage from digestive organs) Inguinal nodes Lymphatics KEY: Drained by the right lymphatic duct Drained by the thoracic duct Figure 12.3

13. Germinal center in follicle Capsule Afferent lymphatic vessels Subcapsular sinus Trabecula Afferent lymphatic vessels Efferent lymphatic vessels Hilum Cortex Medullary sinus Follicle Medullary cord Figure 12.4

14. Lymph enters the convex side through afferent lymphatic vessels Lymph flows through a number of sinuses inside the node Lymph exits through efferent lymphatic vessels Fewer efferent than afferent vessels causes flow to be slowed Flow of Lymph Through Nodes

15. Several other organs contribute to lymphatic function Thymus Spleen Peyer’s patches Tonsils Other Lymphoid Organs

16. Tonsils (in pharyngeal region) Thymus (in thorax; most active during youth) Spleen (curves around left side of stomach) Peyer’s patches (in intestine) Appendix Figure 12.5

17. Located low in the throat, overlying the heart Functions at peak levels only during childhood Produces hormones (like thymosin) to program lymphocytes (T Cells) Thymus Gland

18. Located on the left side of the abdomen Filters blood Destroys worn out red blood cells Returns iron to the liver for hemoglobin production Acts as a blood reservoir Spleen

19. Found in the wall of the small intestine Resemble tonsils in structure Capture and destroy bacteria in the intestine Peyer’s Patches

20. Small masses of lymphoid tissue around the pharynx Trap and remove bacteria and other foreign materials Tonsillitis is caused by congestion with bacteria Tonsils

21. Includes Peyer’s patches Tonsils Other small accumulations of lymphoid tissue Acts as a sentinel to protect respiratory and digestive tracts Mucosa-Associated Lymphatic Tissue (MALT)

22. The body is constantly in contact with bacteria, fungi, and viruses The body has two defense systems for foreign materials Nonspecific (innate) defense system Specific (adaptive) defense system Together they make up the immune system Body Defenses

23. Nonspecific defense system Mechanisms protect against a variety of invaders Responds immediately to protect body from foreign materials Specific defense system Specific defense is required for each type of invader Commonly referred to as the immune system Body Defenses

24. Body Defenses Figure 12.6

25. Body surface coverings Intact skin Mucous membranes Specialized human cells Chemicals produced by the body Nonspecific Body Defenses

26. Phagocytes (neutrophils and macrophages) Engulfs foreign material into a vacuole Enzymes from lysosomes digest the material Defensive Cells Figure 12.7a

27. Events of Phagocytosis Figure 12.7b

28. Triggered when body tissues are injured Produces four cardinal signs Redness, Heat, Swelling and Pain Results in a chain of events leading to protection and healing Inflammatory Response - Second Line of Defense

29. Prevents spread of damaging agents Disposes of cell debris and pathogens Sets the stage for repair Functions of the Inflammatory Response

30. Steps in the Inflammatory Response Figure 12.8

31. Abnormally high body temperature Hypothalmus heat regulation can be reset by pyrogens (secreted by white blood cells) High temperatures inhibit the release of iron and zinc from liver and spleen needed by bacteria Fever also increases the speed of tissue repair Fever

32. Antigen specific – recognizes and acts against particular foreign substances Systemic – not restricted to the initial infection site Has memory – recognizes and mounts a stronger attack on previously encountered pathogens Specific Defense: The Immune System – Third Line of Defense

33. Humoral immunity (B cells) Antibody-mediated immunity Cells produce chemicals for defense Cellular immunity (T cells) Cell-mediated immunity Cells target virus infected cells Types of Immunity

34. Any substance capable of exciting the immune system and provoking an immune response Examples of common antigens Foreign proteins Nucleic acids Large carbohydrates Some lipids Pollen grains Microorganisms Antigens (Non-self)

35. Your B cells encounter antigens and produce antibodies Active immunity can be naturally or artificially acquired Active Immunity Figure 12.14

36. Antibodies are obtained from someone else Conferred naturally from a mother to her fetus Conferred artificially from immune serum or gamma globulin Immunological memory does not occur Protection provided by “borrowed antibodies” Passive Immunity

37. Major types of grafts Autografts – tissue transplanted from one site to another on the same person Isografts – tissue grafts from an identical person (identical twin) Allografts – tissue taken from an unrelated person Xenografts – tissue taken from a different animal species Organ Transplants and Rejection

38. Autografts and isografts are ideal donors Xenografts are not very successful Allografts are more successful with a closer tissue match Organ Transplants and Rejection

39. Abnormal, vigorous immune responses Types of allergies Immediate hypersensitivity Triggered by release of histamine from IgE binding to mast cells Reactions begin within seconds of contact with allergen Anaphylactic shock – dangerous, systemic response Disorders of Immunity: Allergies (Hypersensitivity)

40. Types of allergies (continued) Delayed hypersensitivity Triggered by the release of lymphokines from activated helper T cells Symptoms usually appear 1–3 days after contact with antigen Disorders of Immunity: Allergies (Hypersensitivity)

41. Production or function of immune cells or complement is abnormal May be congenital or acquired Includes AIDS – Acquired Immune Deficiency Syndrome Disorders of Immunity: Immunodeficiencies

42. The immune system does not distinguish between self and non-self The body produces antibodies and sensitized T lymphocytes that attack its own tissues Disorders of Immunity: Autoimmune Diseases

43. Examples of autoimmune diseases Multiple sclerosis – white matter of brain and spinal cord are destroyed Myasthenia gravis – impairs communication between nerves and skeletal muscles Juvenile diabetes – destroys pancreatic beta cells that produce insulin Rheumatoid arthritis – destroys joints Disorders of Immunity: Autoimmune Diseases