Immune System: Lymphatic System What you must know:

1. Immune System: Lymphatic SystemWhat you must know: • Several elements of an innate immune response • The differences between B and T cells relative to their activation and actions. • How antigens are recognized by immune system cells • The differences in humoral and cell-mediated immunity • Why Helper T cells are central to immune responses

2. Recognition of traits specific to particularpathogens, using a vastarray of receptors • • Recognition of traits sharedby broad ranges ofpathogens, using a smallset of receptors Animals are the only organisms with major immune systemsAll animals possess a degree of innate immunityVertebrates also posses and adaptive immune response that can respond to specific pathogens Pathogens(such as bacteria,fungi, and viruses) Barrier defenses: SkinMucous membranesSecretions INNATE IMMUNITY(all animals) Internal defenses: Phagocytic cellsNatural killer cellsAntimicrobial proteinsInflammatory response • Rapid response ADAPTIVE IMMUNITY(vertebrates only) Humoral response: Antibodies defend againstinfection in body fluids. Cell-mediated response: Cytotoxic cells defendagainst infection in body cells. • Slower response

3. Lymphatic System and ImmunityCh. 14 p. 377 Lymphatic system is a network of vessels that… transport excess fluids, absorbs fats, and helps protect against disease. Leukocytes patrol the circulatory system

4. 3 parts of Immune System 1. Lymphatic vessels • Function: carries fluid back to blood from the tissues so blood can have a sufficient amount of volume • Cell Debris, bacteria and virus can easily enter the lymph capillaries but not blood capillaries 2. Lymph nodes • Function: contains phagocytic cells and lymphocytes to help protect the body by removing foreign material from the lymphocytes (immune response). Collect pathogens and immune surveillance (lymphocytes and macrophages) • Location: along the lymphatic pathway. Large clusters found with the connective tissue of the groin, under arm and neck regions • 3. Organs- Spleen, thymus, tonsils and Peyer’s Patches

5. Structure of Lymph 2. Lymph nodes continued • Nodes contain several chambers that hold the macrophages and lymphocytes • Macrophages – engulf and destroy bacteria, viruses and other foreign substances • Lymphocytes- respond to specific foreign substances, attacks virus bacteria, etc. • Nodes can become secondary cancer sites if they get to large a number of the infectious cells

6. What are White Blood Cells (WBC) • 1% of our blood • Also called leukocytes • Immunity cells • Fight infection • Inside bone marrow • stored in blood and Lymphatic tissue Other blood cell types Red Blood Cells (RBC)- bioconcave shape cells transport oxygen to cells and tissues of the body through blood circulation. Also transport carbon dioxide to the lungs Platelets- these blood cells are vital for the clotting process which is needed to prevent blood loss

7. Types of White Blood Cells • Granulocytes • Neutrophils- acute infection • Basophils • Eosinophil • Agranulocytes • Monocytes – become macrophages and perform phagocytosis • Lymphocytes- specific immune response cells (B and T)

10. 3. Lymph Organs • Spleen – blood-rich organ that filters blood and destroys worn out red blood cells and returns pieces to liver. Cleans blood • Stores platelets and is a blood reservoir • Fetus – spleen makes red blood cells • Adult – makes lymphocytes • Thymus – found overlying the heart and produces hormones (Thymosin) that program T lymphocytes

11. 3. Lymph Organs • Tonsils – small masses of lymphatic tissue around the pharynx that protects the respiratory system ◦Traps and removes bacteria and other foreign substances before they can enter the throat • Peyer’s Patches – found in walls of intestines and protects the digestive system from bacteria, viruses, and other harmful substances . Tonsils of intestine

12. Innate Immunity =“ non specific”

13. Resistance • Resistance is your bodies ability to defend against pathogens. • Your immune system gives you resistance. Lymphatic system/Immune System

14. Nonspecific (Innate) immune defenses- responds immediately to protect body fromall foreign substances The immune system protects your body from pathogens Antigens = any substance capable of exciting an immune response Pathogens = types of antigen that is a harmful or disease causing microorganisms This system is composed of mechanical barriers that cover body surfaces, cells and chemicals that initially act to protect the body against pathogens. Prevents entry.

15. Mechanical barriers- first line of defenseHow do skin and mucous membrane protect body? • Skin secretes acidic substances, stomach mucosa is acidic, saliva can kill bacteria, stick mucous in digestive tract can trap microorganisms • When surface barrier is broken other nonspecific responses occur

16. 1. physical barriers to disease • Nonspecific defense. • Skin-water proof barrier • Sweat, oils, & waxes. • Mucous membranes (lysozyme- enzyme disrupt bacterial cell walls-found in tears and saliva & secretions) • Cilia epithelium in respiratory tract, traps pathogens • HCl of stomach.

17. 2. Inflammatory Response- 2nd line of defense • Inflammatory response occurs when pathogen penetrates the skin whenever body tissue is injured • Symptoms: • Redness • Heat • Swelling, pain • Prevents • Spread of damaging agents, disposes cell debris and pathogen and sets the stage for repair

18. 2. Inflammatory Response- 2nd line of defense • What occurs: • Damaged cells (mast cells) release histamines. • Causes vasodilation • Causes increase in permeability. • Deliver clotting agents, phagocytic cells Histamine is an amine chemical that plays a role in many inflammation response and allergic reactions, causes runny nose and sneezing Antihistamines- work in preventing the release of histamines by blocking allergic reactions Pair share: explain this picture to your partner. What is happening in each frame?

19. 6. Mast Cells- Induces inflammation releases histamine and allergic reactions, wound healing 7. Histamine is causes 1. vasodilation, widens blood vessels 2. induces fluid section at the site of infection for inflammatory response

20. 3. Cells (White blood cells) • A. Natural Killer (NK) cells – found in blood , lymph and can kill cancer cells and virus infected cells; can act against any foreign cell. Kills by puncturing cell membrane. May be cytotoxic (cell killing) and used as a form of immunoregulation • B. Phagocytes (macrophage)- engulfs foreign substance and breaks it down

21. Phagocytes • Population of white blood cells that patrol the circulatory and lymphatic systems • They phagocytize and digest material that they do not recognize • Following phagocytosis, pieces of pathogens are presented to specific immune system for possible specific responses Phagocytosis means engulfing of microorganisms or other cells and foreign particles by phagocytes

22. C. Macrophages- “big eaters” • Type of WBC • Stationed in certain tissues. • Destroy by phagocytosis. • Rid the body of debris and damaged cells.

23. D. Neutrophils – “engulfs” • Most common white blood cell • Kill pathogens using phagocytosis. • Circulate in blood stream. • Migrate towards site of infection. • Move out of the blood stream

24. 1. Neutrophils- first responders at the site of infection kills pathogens, immune defense • 2. Macrophages- engulfs foreign pathogens, cancer cells, stimulate response of other immune cells and becomes an antigen presenting cell • 3. Eosinophils defense against parastie and bacteria, causes tissue damage • 4. Dendritic cell presents antigens on it surface triggers adaptive immunity • 5. Natural Killer cells kills tumor cells and virus infected cells by puncturing cells • 11 Monocytes immune surveillance differentiates to macrophage and dendritic cell in response to inflammation

25. 4. Antimicrobial Chemicals • A. Complement – proteins that attach to and break apart foreign cells, which amplifies the inflammatory response. Enhances inflammatory response • B. Interferon – signaling proteins released by virus-infected cells that protect uninfected cells from viral takeover

26. Proteins • 12. Cytokines- “cell movement” cell messenger molecue plays a role in inflammation and immunity, bind to specific receptors on target cell • 13. Interleukins (group of cytokines) secreted signal molecule mediates cell communication and stimulates immune response

27. 5. Fever (2nd line of defense) • Pathogens that attack human body like 98.6° F best. • Raising temperature of body increases effectiveness of white blood cells (WBC). • Abnormally high body temperature inhibits multiplication of bacteria • Systemic response triggered by pyrogens (chemicals secreted by white blood cells and macrophages that have been exposed to foreign cells) • Enhances repair processes

28. 5. Fever

29. Plant Defenses • Nonspecific responses • Receptors recognize pathogen molecules and trigger defense responses • Thicken cell wall, produce antimicrobial compounds, cell death • Localize effects

30. summary • List 3 nonspecific defense barriers. • List 3 symptoms of the inflammatory response. • What do macrophages do?

31. Specific Immune Response 3rd line of defense

32. Specific Defense System • Attacks very specific foreign substances – either direct cell attack or by releasing antibodies- and acts to destroy or inactive them • Must encounter a substance (antigen) before it can protect the body against it

33. Immune Response • Immune system’s response to a threat that starts with the inflammatory response and then attacks specific antigens • Body will attack anything that is recognized has not being part of the body

34. 3 Characteristics of the Immune Response • Antigen specific- acts on particular pathogens • Systemic – not restricted to infection site • Has memory – recognizes and has even stronger attacks on previously encountered pathogens

35. Types of Immunity 1. Humoral Immunity – antibody mediated • Provided by antibodies present in body’s fluid 2. Cellular immunity- cell mediated • When lymphocytes (living cells) defend the body

36. Antigen-presenting cellsenting cell Cell-Mediated Immune Response (T Cells) Humoral Immune Response (antibodies) Helper T cell B cell Cytotoxic T cell Plasma cell tag for destruction Identify and destroy Infected cell Antibodies

38. Lymphocytes ( 2 TYPES) • Formed in red bone marrow • 1. B Cells – produce antibodies and oversee humoral immunity • Plasma cells  antibody • 2. T cells –non antibody producing lymphocytes that make up cell mediated immunity • Mature in thymus • Helper T cells and cytoxic T Our genes, not antigens, determines what specific foreign substances our immune system will recognize and resist

39. Adaptive Response

40. MACROPHAGES • Do not respond to specific antigens but help lymphocytes • Engulf antigens and break them down • Leave parts of antigens on their surface so T cells can recognize the antigen • Become antigen presenting cells

42. Humoral (Antibody-Mediated) Immune Response • B lymphocyte finally matures and activates when it binds to an antigen or it is stimulated by Helper T cells • Clonal selection – B lymphocytes are selected out of billions and begin to grow and multiple rapidly • Cloned lymphocytes (antibodies) are primary humoral response to antigens

43. Humoral (Antibody-Mediated) • B cells turn into plasma cells (rapid multiplication) or memory cells (long lived and can respond to antigen later) • - Blood antibody levels rise and then decline • - Secondary responses are with memory cells – faster, more prolonged, and more effective

45. Types of Immunity • Passive = receiving antibodies from a donor (mother to fetus) or through an injection of immune serum; temporary • Active = response to encountering an antigen or injection of vaccine in order to produce the antibodies; permanent

46. Active and Passive Humoral Immunity • Active Immunity – B cells encounter antigens and produce antibodies • ◦Naturally acquired – during infections • ◦Artificially acquired – receive vaccines • ◦Vaccines spare us from most signs and symptoms and can stimulate antibodies to fight off antigen

47. Passive Immunity getting antibodies from another immune human or animal donor • Naturally acquired – antibodies from mother during fetal development • ◦Artificially acquired – received from immune serum

48. Antigen: substance that elicits lymphocyte response • Antibodies (immunoglobulin – Ig): part of blood proteins made by B cell and each only binds to one antigens

49. Antibody responses Primary response occurs the first time exposure to pathogen occurs. Secondary response occurs when pathogen invades again. Faster reaction. Stronger reaction. Memory B cells.

50. Antibody structure – Y shape Part of blood proteins and each type only binds to one antigen. Antibodies match proteins of pathogen. The two arms (short and long) of theantibody are identical, but ends are different. Y shape All antibodies have a region that is the same and a region that allows them to bind to specific antigen