Lymphatic and Immune system

1. Lymphatic and Immune system • Chapter 17

2. TortoraPages 454-455 Lymphatic System • System consists of • Lymph fluid • Lymphatic vessels • Structures and organs consisting of lymphatic tissue • Red bone marrow • Lymphocytes

3. TortoraPage 456 Functions of Lymphatic System • Draining interstitial fluid • Transporting lipids and lipid soluble vitamins A,D, E, and K • Carries out immune responses

4. Lymphatic and Interstitial fluid • Same fluid - different areas. • Interstitial fluid bathes cells. • Lymphatic fluid is I.F. in lymphatic vessels. • Contains same materials as plasma except no proteins

5. Tortora 456 Lymphatic capillaries • Lie between cells • Open • Collect interstitial fluid. • Fluid moves due to pressure. • Flaps open, allow fluid in, then close

6. Tortora pg 457 Lymphatic Vessels • Lymphatic vessels • Carry lymph fluid • Similar structure as veins with • Thinner walls & more valves. • Skeletal and muscular pumps move it towards the heart.

7. Tortora 456-457 Return to veins • Lymphatic fluid is returned to circulatory system via the jugular & subclavian veins • 20 L of plasma become IF every day • 17 L goes back to heart via the veins • 3 L becomes lymph

8. Tortora pg 458-459 Lymph Nodes • Located along lymphatic vessels. • Arranged in groups. • Afferent vessel leads to node. • Efferent leads away. • Valves do not let lymph fluid move backwards.

9. Tortora pg 458 Lymphatic nodes • 600 located in the body • Concentrated at axillae, mammary glands, throat and groin • Foreign materials are filtered and destroyed in nodes. • Macrophages destroy by phagocytosis • Lymphocytes destroy by a variety of immune responses

11. Macrophages Two cross sections of a lymph node: macrophages, which appear as red in the top image, are sticky cells that act like flypaper, trapping viruses and bacteria when they enter the lymph node. Green and blue show other structural elements of the node. In the bottom picture, B cells are red and the structural elements of the node are in green and blue

12. Swollen lymph nodes

13. Tonsils & spleen • Tonsils: • Large nodules grouped together. • Contains T and B lymphocytes. • Spleen • Largest mass of lymphatic tissue. • Stores blood. • Stores 1/3rd of the body’s platelets • Destroys broken RBCs & platelets.

14. Tortora 458 Thymus gland • Contains T cells, dendritic cells, and macrophages. • Immature T cells arrive here from the red bone marrow. • 2% “graduate” to be mature T cells. • Mature T cells leave the thymus via the blood, are carried to the lymph nodes, spleen, and other lymphatic tissues.

15. Thursday 5/8/03Pages 383-388 Lymph Circulation • Fluid from plasma of blood. • Interstitial fluid. • Lymph Vessels and nodes • Lymphatic capillaries • Lymphatic vessels. • Lymph nodes. • Back to plasma.

16. Thursday 5/8/03Pages 383-388 Lymph Circulation • Lymph fluid is moved by; • Skeletal muscles compressing vessels. • Valves insure one way flow. • Edema • Fluid gain in the interstitial spaces. • Can be due to blocked lymphatic vessels or nodes.

17. Monday 5/12/03Pages 388-388 Innate Resistance to Disease • Pathogens are disease causing organisms. • Pathogens produce toxins or toxic waste products. • Your ability to ward off pathogens is resistance. • Lack of resistance is susceptibility.

18. Monday 5/12/03Pages 388-388 Skin & Mucous Membranes • Skin is 1st defense against pathogens. • Mechanical factors • Many layers of epithelial cells. • Role of keratin. • Role of Mucus membranes. • Mucus • Cilia • Role of lacrimal apparatus • Role of Saliva

19. Monday 5/12/03Pages 388-388 Skin & Mucous Membranes • Chemical Factors factors; • Oil glands secrete sebum. • Perspiration • Lysozymes • Gastric juice • Vaginal Secretions.

20. Monday 5/12/03Pages 388-388 Defenses Against Microbes • Second line of defense. • Interferon • Proteins produced by cells infected by viruses. • Binds to receptor sites of other cells. • Complement • Group of about 20 proteins. • Found in the plasma of blood. • Inhance immune system.

21. Monday 5/12/03Pages 388-388 Defenses Against Microbes • Natural killer cells • Type of lymphocyte. • Ability to kill microbes and some cancer cells. • Located in spleen, lymph nodes, bone marrow, and blood. • Phagocytes • Macrophages are monocytes that morph. • Wandering and fixed. • Neutrophils • Hi

22. Phagocytosis • Chemotaxis • Phagocytes move towards higher concentration of chemicals. • Adherence • Phagocytes attach to microbe. • Role of complement. • Ingestion • Pseudopod surrounds microbe. • Phagocytic vesicle is formed. • Vesicle fuses to lysosome. • Microbe is digested. • Wastes are released by exocytosis.

23. Inflammation • Caused by pathogens, abrasions, chemical irritations. • Symptoms • Redness • Pain • Heat • Swelling

24. Inflammation • Stages of inflammation • Vasodilation& increased permeability of blood vessels. • Phagocyte migration. • Usually within an hour. • Chemotaxis & emigration • Repair

25. Fever • The hypothalamic thermostat resets to raise body temp. • Reason: higher temps inhibit antigen replication, but speeds up interferon and body repair

26. Innate and Adaptive Immunity • Innate immunity is a generalized response • Adaptive immunity refers to “specific” response to certain pathogens. • An antigen is any substance that triggers an immune response. • The immune system carries out immune responses to antigens • Self-tolerance is when a body does not attack its own tissues and chemicals. Lack of self tolerance results in autoimmune diseases.

27. 2 forms of adaptive immunity • Cell mediated immunity: • Cells directly attack a specific antigen (pathogens) • Antibody mediated immunity: • Antibodies are produced to attack specific antigen. • Both use mature T and B cells • 2 types work together to remove infection

28. T Cells and Cell Mediated Immunity • Recognizing self from nonself :MHCs • Major histocompatibility complex proteins recognize non-self antigens • Role of MHCs in transplants • T Cells destroy antigens: • Macrophages present antigen to T cells. • T cells sensitize. • T cells clone. • Lyse infected cells

29. TortoraPages 465-467 Antibodies and antigens • Antigens can be • Whole pathogens • Toxins • Parts of pathogens • Antigens + interleukin-2 induce plasma cells to secrete proteins called antibodies (immunoglobulins) • Shaped like a “Y” • One arm is always the same. • Other 2 arms are specifically shaped to antigen.

30. Antibody action • Antibodies travel to the infection site, bind to the antigen, and inactivate it.

31. How Antibodies affect antigens • Neutralize the antigen toxins • Immobilize bacteria. • Agglutination- antigens are stuck together

32. Memory cells • Converted B lymphocytes • B lymphocytes were shown the antigen by macrophages. • B cells now recognize antigen. • Some B cells become memorycells

33. TortoraPages 428-437 B Cells and Antibody-Mediated immunity • Long-lasting antibodies and lymphocytes “remember” the invading antigen • If the body is ever re-exposed, it will launch a swift attack • Primary response • Slower to develop • Secondary response • Much faster and stronger.

34. Primary and secondary response

35. Vaccines and immunological memory • Vaccines contain weakened, killed microbes or parts of microbes. • Without getting sick,your body launches an immune response, activating B and T cells • If you are ever exposed, your body will quickly remove the antigen. • Some vaccines need “booster shots” to remain effective ( tetanus)

36. Types of Immunity • Naturally acquired active immunity. • Response to pathogens in every day life. • Naturally acquired passive immunity. • Natural transfer of resistance. Nursing baby. • Artificially acquired active immunity. • Acquired through vaccinations. • Artificially acquired passive immunity. • Intravenous injection of antibodies.